Trey Songz walloped a bartender with his fist at a concert, then went right back to watching the show ... so the bartender claims in a new lawsuit.
The singer's being sued for battery by a man who says he was tending bar around midnight at the Hollywood Palladium on May 9, 2019 ... and claims Songz was part of the crowd.
According to the legal docs, obtained by TMZ, the bartender says Songz jumped on the bar to sit and watch the show ... which the bartender insists is against the venue's policy.