Dirk Nowitzki, Steve Nash & Luka Doncic Compete In Tennis Tourney For Charity

Dirk Nowitzki, Steve Nash and Luka Doncic ditched basketballs for rackets this weekend -- hitting tennis courts in Dallas for charity -- and it turns out the trio of hoopers have no issues whatsoever channelin' their inner-Serena Williams!!

The Dallas Mavericks icons -- plus Ben Stiller and a whole host of other celebs and athletes -- all competed in the fifth-annual Dirk Nowitzki Pro Celebrity Tennis Classic on Sunday ... and they looked GOOD.

The NBA ballers partnered up with some of the biggest names in tennis for the tournament, including Andy Roddick and Mark Knowles ... and they went at it at the SMU Tennis Complex for hours.

The guys showed off some serious athleticism, hitting big-time shots -- all while joking around with each other.

In fact, at one point, Stiller hilariously dissed Nowitzki with a fake handshake after a match!

Nash, though, ended up getting the last laugh on everyone ... the Brooklyn Nets head coach came out on top of the tourney after he and his partner, Spencer Papa, defeated British tennis star Luke Bambridge and his partner, Leo Antonio.

It all looked like a great time ... but the best part? The proceeds from the tourney are going to Nowitzki's foundation -- which focuses on children's wellbeing, health and education.