Ex-NBA star Tom Chambers certainly did -- admitting he got physical with a trash-talking 22-year-old at an Arizona bar ... and now he's been charged with assault.

It all stems from an April 15 incident at Isabella's Kitchen in Scottsdale -- where Tom says he was innocently hanging out when another patron started insulting him.

Witnesses told police the other patron, Alexander Bergelt, began to take verbal jabs at Tom including, "You're not sh*t," "You're tall and scrawny" and "Look at your big head."

Tom told police the final straw came when Bergelt said, "Your mom should have killed you when you came out of the womb as ugly as you are, your arms are skinny, your chest is this. Your belly is big."

Tom admits he "absolutely put hands on [Alexander]" but never punched him. Tom says he was trying to get Alexander to "show respect."

Alexander told police a different story -- saying Chambers came at him from across the bar, grabbed him by the throat and threw him backwards.

Cops say Alexander had a mark on his neck and a bruise on his lip.

When cops arrived, Alexander told police all he wanted was an apology -- he didn't get it.

Cops investigated and decided to press charges against both parties -- Chambers was hit with assault and Alexander was charged with disorderly conduct.

Chambers was a 4-time NBA All-Star and famously had one of the greatest dunks in NBA history over Mark Jackson.