Kim Kardashian's Sisters Read Her for Filth as a 'Liar' and 'Cheater' When She Gets 'Competitive' (Exclusive)

Kim Kardashian has no qualms about playing dirty.

In PEOPLE's exclusive sneak peek of The Kardashians ahead of the show's season 4 premiere, Kim and Khloé Kardashian go head to head with their younger sisters Kylie and Kendall Jenner in a guacamole-making competition during their family trip to Cabo San Lucas.

“We are all very competitive people in a very healthy way,” Khloé, 39, tells the cameras as the scene shifts to the SKIMS founder vigorously mixing avocados. “I think Kim is the most competitive.”

“I am competitive,” Kim, 42, agrees in a confessional. “Who doesn't like to win? Would I be lying and saying I love to be a loser? You know, like who says that?"

With five minutes on the clock, the mom of four decides to intervene and gets caught red-handed when Kendall, 27, spots her picking vegetables off of her bowl of guacamole to place into her own. 

“You can’t take from ours! Put it back,” Kendall chastises her. “Kimberly, cheater!”

Despite getting caught with her hand in the cookie jar, Kim denies being a “dirty fighter” and tells the cameras that she believes that her “talent” will “get me far enough to win.”

“I don’t play dirty,” she adds, while Khloé confirms Kim’s history of bending the rules. “Please, Kim used to have me make her cupcakes and frost them, and then I would leave and she would tell her boyfriends that she made them all.”

As Kendall warns her older sister to keep her hands away from their guacamole dish for the second time, Kylie, 26, and Kendall appear in a joint confessional where they discuss Kim's competitive tendencies.

“Kim plays so dirty,” Kylie says as Kendall claims, “She’s a goddamn liar.”

"And she's a cheater, is what she is,” the Kylie cosmetics founder laughs as the supermodel agrees. 

The scene shifts to another shot of Khloé attempting to discreetly push Kendall and Kylie’s homemade tortillas on the floor with her nails. The act doesn’t go unnoticed as Kylie exclaims, “Khloé! You know I worked really hard on these!”

“They're sabotaging us,” Kendall continues to the cameras and Kylie adds, “They know they're gonna lose.”

Kylie continues, “Can you blame them really? I wasn't even paying attention… I was just tunnel vision to my craft and what we were there to do, which was win.”

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Season 4 of The Kardashians premieres Thursday, Sept. 28 at 12 a.m. ET on Hulu.