Atlanta Hawks star Dennis Schroder shoved another man outside of a hookah bar in Georgia early Friday morning -- triggering a group beatdown that was all caught on video ... TMZ Sports has learned. 

We've obtained the police report which shows the 24-year-old NBA star was hanging out with a group of friends around 2AM at a restaurant called 6AM, which is connected to a hookah bar. 

Cops say they were called in response to a fight and when they arrived Schroder and his crew were trying to leave. 

Cops found surveillance video which show Schroder and his friends in a "verbal heated exchange" with another man. But things escalated when Schroder threw the first shove -- triggering his friends to basically jump the guy. 

"[The victim] was struck by hands and feet by the offenders."

Eventually, security broke up the fight. The victim was transported to the hospital with what appeared to be non-life threatening injuries. 

Schroder and his 3 friends were all arrested for battery

The surveillance video was collected and submitted as evidence. Guessing the Hawks are gonna wanna see that.