Recent rivals, Cuban, owner of the Dallas Mavericks, and Ballmer, owner of the Los Angeles Clippers, appeared on the Kiss Cam mid-game, smiling amid a crowd of cheering fans.
The billionaires' rivalry began in July when center DeAndre Jordan verbally agreed to a four-year deal with the Mavericks, but ultimately re-signed with the Clippers. Jordan's four-year contract is estimated to be worth $88 million, according to ESPN.
"I mean, I don't hate the Clippers," Cuban said before the game, according to ESPN. "That's a strong word. I don't hate anybody on the Clippers. I pretty much hate anybody who doesn't have Mavericks or Dallas across their chest, but again, I just don't give a [expletive] about the Clippers. Maybe that explains it."
The Clippers ultimately beat the Mavericks 104 to 88. Neither camp immediately responded to CNBC's request for comment.
Social media users took to Twitter on Thursday to comment on the exchange between owners.
Ballmer formerly ran Microsoft and Cuban is a longtime tech entrepreneur.