Virgil van Dijk transformed Liverpool into the force they are today, Leicester snapped up Riyad Mahrez for just £400,000 and few can match Bruno Fernandes' stunning impact... but who takes the No 1 spot in our top 10 Premier League signings EVER?

• e-mail

The January transfer window opens tomorrow for those in the Premier League, as clubs get the opportunity to improve on their squads going into the business end of the campaign. 

The window is typically a quieter period than in the summer, with perhaps the most notable transfers last time out being loan moves for Jesse Lingard and Martin Odegaard to West Ham and Arsenal respectively, alongside Amad Diallo's big-money switch to Manchester United. 

Many of the Premier League's best-ever signings have come in the January transfer window, however, and with a fierce battle ahead - both at the top and bottom of the table - it wouldn't be overly surprising to see a number of high-profile moves once more. 

All eyes will be on Newcastle as they enter their first window since their Saudi-led takeover, while it will also be interesting to see what Tottenham and United do under Antonio Conte and Ralf Rangnick.

As has been particularly on show in recent history, a mega-money signing in January can provide a major boost heading into the second half of the season, while we've also seen a number of hidden gems unearthed over the years.  

And as we approach another enticing window, Sportsmail takes you through the top 10 Premier League signings in January window history.

10. Chelsea sign Gary Cahill (2012)

Gary Cahill, whose immense impact for Chelsea following his £7m transfer from Bolton in 2012, is often underappreciated. 

Certainly not the most glamorous of singings Chelsea have made in the Roman Abramovich era, but one that undoubtedly contributed to their recent success. 

Arsenal and Tottenham had also both been keen on the centre-back, then 26, but his decision to join Chelsea instantly proved to be the right one.

Gary Cahill (centre) won the Champions League with Chelsea within six months of his arrival

Cahill started as Chelsea claimed their first-ever Champions League trophy with an historic penalty shootout win over Bayern Munich, while also winning the FA Cup - though he missed the final with a hamstring injury - all within six months of his arrival. 

The Englishman would go on to win two Premier League titles, two FA Cups, a League Cup, two Europa Leagues and, of course, the Champions League.   

Cahill was named in the PFA Team of the Season three times while at Chelsea and was given the unenviable job of replacing John Terry as club captain in 2017 - a duty he handled without question -  before eventually leaving in 2019. 

9. Everton sign Seamus Coleman (2009)

Seamus Coleman, who, of course, doesn't quite have the trophy haul of others on the list, in fact yet to claim any silverware at Everton, but his ridiculous transfer fee puts him up there with the best January signings ever. 

Everton snapped up Coleman from Irish side Sligo Rovers all the way back in January 2009 for a price of just £60,000 and he's gone on to be perhaps their best-ever signing. 

It's easy to forget that Coleman endured a difficult start to life with Everton, having suffered a freak foot infection that threatened to end his career early upon emerging as a fringe contender by the 2009/10 campaign.  

Seamus Coleman has made 363 appearances for Everton since his £60,000 signing in 2009

Coleman was eventually handed his senior debut in October 2009 against Benfica in the Europa League, a game Everton lost 5-0, before claiming two assists against Tottenham in his home debut just two months later.     

The defender moved to Blackpool on loan shortly after, helping the Championship side gain promotion to the Premier League, before returning to Everton the following campaign. 

Coleman has since made 363 appearances for Everton and remains club captain, a position he was given in 2019. 

8. Chelsea sign Branislav Ivanovic (2008)

Once a Fantasy Premier League player's dream, Branislav Ivanovic has to be included in a list of best-ever January transfers. 

Chelsea acquired the in-demand defender from Lokomotiv Moscow in 2008, and similarly to Coleman, he was made to overcome a tricky start on his way to becoming a club legend. 

Ivanovic wouldn't make a single appearance for the Blues in the 2007/08 season having been overlooked by Avram Grant, in a campaign that ended in bitter disappointment as they were beaten by Manchester United in the Champions League final.   

Branislav Ivanovic won three Premier League titles during a successful spell with Chelsea 

The defender - initially bought as a centre-back - later admitted he could have left without ever playing a game for the west London club, but in transitioning to a right-back, he became one of the first names on the team sheet. 

Ivanovic would eventually make 377 appearances for Chelsea, winning three Premier League titles, three FA Cups, a League Cup and both the Champions League and Europa League. In fact, he even scored the all-important stoppage-time winner that sealed the Europa League victory in 2013.  

The truly painful moment in which Ivanovic learned of his suspension for the final of the Champions League in 2012 on live television will forever be membered, but so will his brilliant consistency in defence, which saw him named in the PFA Premier League Team of the Year twice.

7. Arsenal sign Pierre-Emerick Aubameyang (2018)

Next up is Pierre-Emerick Aubameyang, who has to go down as one of the best-ever January signings regardless of his precarious position with the club as things stand. 

Arsenal splashed out a club record £56m for the striker, who had built a fearsome reputation as one of Europe's finest finishers while at Borussia Dortmund. 

The Gabon international had notched 141 goals in 213 games for Dortmund and arrived in hot form, having scored 21 in 24 during the first half of the season. 

Pierre-Emerick Aubameyang lead Arsenal to FA Cup glory with victory over Chelsea in 2020

Aubameyang immediately hit the ground running, scoring 10 league goals in just 13 Premier League outings. And in his first full season, he shared the Golden Boot award with Mohamed Salah and Sadio Mane, all ending the campaign on 22 goals. 

The forward would then score a further 22 league goals the following season, alongside leading the Gunners to FA Cup victory with braces in both the semi-final and final against City and Chelsea respectively.  

The last season-and-a-half have been difficult for Aubameyang, who was recently stripped of his captaincy following a third disciplinary breach, but as January signings go, he certainly goes down as one of the best. 

6. Liverpool sign Philippe Coutinho (2013)

This proved to be a phenomenal signing for two reasons: firstly, having performed to an exceptional standard for numerous years, but secondly due to his eventual price tag when leaving for Barcelona. 

Having struggled for game time at Inter Milan, Brendan Rodgers bolstered his attack with the exciting £8.5m acquisition of the talented 20-year-old in 2013, adding to the recent signing of Daniel Sturridge. 

Coutinho would go on to play 201 games for the Merseyside club, scoring 54 goals, recording 45 assists and establishing himself as the creative heartbeat of the Liverpool team. 

Philippe Coutinho's departure to Barcelona proved to be a pivotal moment in Liverpool history

However, it was ironically in his departure that Coutinho truly allowed the club to progress. In a move sanctioned by Jurgen Klopp, having already had his heart set on a move away over the summer, the Brazilian finally completed a stunning £145m move to Barcelona in January. 

Particularly without a ready-made replacement, many at the time thought the exit could prove disastrous for Liverpool, but it turned out the opposite, as they used the money to fund moves for Van Dijk and subsequently Alisson Becker. 

While Liverpool have gone strength-to-strength since the midfielder's departure, Coutinho has experienced a nightmare spell at Barcelona, which looks like it could come to an end in the next few weeks. 

5. Leicester sign Riyad Mahrez (2014)

Few, if any, could have anticipated the impact Riyad Mahrez would make upon completing his signing for Leicester in 2014. 

Now playing for Manchester City and widely regarded as one of the best attacking talents in world football, it's perhaps remarkable to think that Leicester paid just £400,000 for the then 22-year-old from Ligue 2 side Le Havre.  

Mahrez had scored six goals in 60 games in five years with the French side.  

With Nigel Pearson at the helm, Leicester earned promotion from the Championship, though Mahrez managed just three goals in 19 league outings in his debut season. 

Riyad Mahrez sensationally won the Premier League title with Leicester back in 2016

The following campaign was remarkable for a number of reasons. Leicester ended up finishing 14th in the Premier League after claiming seven wins and a draw in their last nine games, earning more points (22) than any other side in that period. That's despite being sat bottom of the table and seven points off safety with 10 games remaining. 

Mahrez contributed to just seven league goals in that season, but there was clearly a quality player in there. And in the following campaign, where new manager Claudio Ranieri incredibly led Leicester to the title, Mahrez scored 17 goals and assisted 10.    

The Algerian would eventually leave for City in 2018 for a whopping £60m, marking a profit of over £59m for Leicester. Incredible.  

4. Liverpool sign Luis Suarez (2011)

Now we have Luis Suarez, who completed a £22.7m move to Liverpool from Ajax in 2011, remarkably in a deal that was perhaps overshadowed by Andy Carrol's £35m arrival at the time.   

But it was Suarez who set the Premier League alight during his three-and-a-half year stay at Liverpool, where he scored 82 goals in 133 games. 

He perhaps also produced one of the finest individual seasons in Premier League history during the 2013/14 campaign, where he won the Golden Boot with 31 goals goals as Liverpool agonisingly lost out to City in the title race.  

Luis Suarez will be remembered in history as one of the best strikers to play for Liverpool

Suarez was simply a joy to watch and utterly unplayable on his day, but his time at Liverpool was also clouded by controversary.  

Liverpool reluctantly allowed the forward to leave for Barcelona in 2014 in a £75m deal, with Suarez then serving a four-month ban for biting Italy centre-back Giorgio Chiellini during the World Cup in his latest incident.   

Suarez would go on to win the Champions League with Barcelona, alongside four La Liga and Copa del Rey titles, while scoring 195 goals in 283 games for the Catalan giants. 

The Uruguayan has also been prolific at Atletico Madrid, who won the La Liga title last season. 

3. Manchester United sign Nemanja Vidic (2006) 

We start with Nemanja Vidic, whose £7million move from Spartak Moscow to Manchester United in 2006 simply has to go down as one of the best Premier League transfers of all time. 

Sir Alex Ferguson expressed his sheer delight upon the announcement of the signing, revealing he had been scouting the 25-year-old centre-back for three years. 

Nemanja Vidic (left) and Patrice Evra both moved to England in the same January window

United would win the League Cup within two months of Vidic's arrival, before the Serbian went on to win five Premier League titles, the Champions League and a further two League Cups. 

Vidic will be forever known for his formidable partnership with Rio Ferdinand, which many argue to be the best defensive duo to this day.    

It's also worth noting that United signed Patrice Evra in the same window for £5.5m, with the Frenchman also winning five Premier League titles, three League Cups and a Champions League. Not a bad window, really.  

2. Manchester United sign Bruno Fernandes (2020)

The impact Bruno Fernandes made upon his January 2020 arrival was truly astonishing. 

Having been heavily linked with a move to Tottenham, Fernandes finally completed a transfer initially worth £46.6m from Sporting Lisbon, penning a whopping five-and-a-half year contract. 

Despite only arriving in January, Fernandes was named United's player of the season, having inspired the Manchester side to a third-place finish in the Premier League. 

Bruno Fernandes proved an instant hit following his big-money move from Sporting Lisbon

The Portuguese scored eight goals and provided seven assists in his 14 league outings, while also proving instrumental as United reached the semi-finals of the FA Cup and Europa League, though falling short on both occasions.   

Unsurprisingly, Fernandes also won the award for the 2020/21 campaign, having notched 28 goals and 16 assists in all competitions, while guiding United to a second-place finish in the Premier League, albeit losing in the final of the Europa League.    

Fernandes hasn't been quite as prolific this season with United somewhat faltering, but his overall return of 79 goal involvements in 103 games is breathtaking.  

1. Liverpool sign Virgil Van Dijk (2018)

There were plenty of eyebrows raised to say the least as Liverpool announced he £75m acquisition of Virgil Van Dijk from Southampton in 2018, then the highest-ever fee for a defender. 

Jurgen Klopp's side were undeniably vulnerable at the back, though, and after falling short in their pursuit of the defender the previous summer, they finally splashed the cash the following January.  

Van Dijk quickly and emphatically silenced any and all doubters and has since emerged as one of the, if not the, best central defender in world football, playing a significant role in transforming Liverpool into the force they are today. 

The Dutchman played an instrumental role as Liverpool reached the Champions League final within five months of his arrival, though falling short in a 3-1 defeat against Real Madrid.    

Liverpool have won the Premier League and Champions League since Virgil Van Dijk's arrival

Liverpool would develop further in the following season, this time winning the Champions League with victory over Tottenham, while also claiming 97 points in the Premier League, though somehow still finishing below Manchester City. Van Dijk finished as runner-up for the 2019 Ballon d'Or. 

The next season, Liverpool would end their 30-year wait for a Premier League title, with Van Dijk of course at the centre of it all. And though Liverpool suffered immensely in the 2020/21 campaign with the Dutchman largely sidelined throughout due to an anterior cruciate ligament injury, they once again emerged as a genuine force upon his return. 

Remarkably, having sealed his move to Liverpool now four years ago, Van Dijk still hasn't lost a Premier League game at Anfield for the Reds.