What do a Mother’s Day celebration, a new line of Jamaican soft drinks and two soul veterans have in common? Absolutely nothing. But that didn’t stop them from converging at Friday’s concert featuring Bobby Womack and Millie Jackson at the steadily decaying Warner Theatre.

You’d think that almost any show would be ruined by endless production delays and an annoying beverage promotion. But Jackson and Womack earned their stripes back in the days when black performers had to overcome obstacles far worse. And Womack, in particular, displayed the sweat-soaked bravado needed to back up the phrase “the show must go on.”

The endearingly ribald Jackson supplied a high-energy set, performing medleys of her hits and street-talk testimonials to love, spiking soulful but less-than-empowering numbers like “Hurts So Good” with self-help talk. In the middle of her first hit, “If Loving You Is Wrong, I Don’t Want to Be Right,” she stopped and said that if she had recorded the song today, it would be called “If Loving Me Is Wrong, I Don’t Want to Be Right.”

When Womack finally arrived onstage, he was backed by a skimpy five-piece band. “When I played L.A. last night I had about nine more members,” he explained, “but I wasn’t gonna let D.C. down even if it had to be just me and my guitar.” And Womack was true to his word with a short but sprightly set of hits and such audience requests as “If You Think You’re Lonely Now” and “No Matter How High I Get (I’ll Still Be Looking Up to You).” When someone requested “Taxi,” Womack admonished, “That’s not me, that’s by J. Blackfoot.” But being a practiced crowd-pleaser, he sang it anyway.