The round-robin tournament benefitted the Dirk Nowitzki Foundation. (Dallas Mavericks)

If you ever play Dirk Nowitzki in tennis, make sure you watch out for his lethal slice serve from the deuce side, especially on his second-serve.

The NBA legend racked up the aces in his fourth annual Dirk Nowitzki Tennis Classic, a round-robin tiebreak style tournament benefitting the Dirk Nowitzki Foundation.

The event kicked off Saturday night with an auction style dinner. Attendees bid on several once-in-a -lifetime packages, including the chance to sit courtside at a Mavericks game with the German himself.

One of the more sought after packages was a VIP trip to the BNP Paribas Open, which includes a hitting session with both Nowitzki and Tommy Haas.

Participants included Steve Nash, Luka Doncic, Haas, John Isner, Mark Knowles, J.J. Barea, Devin Harris, Dwight Powell, Boris Kodjoe and Mitchell Krueger.

 
 
 
 
 
 
 
 
 
 
 
 
 

had a great time at @thednfoundation !!????????

A post shared by Luka Doncic (@lukadoncic) on

In the end, Haas and former North Texas standout Kseniya Stone edged out Nash and former Fighting Illini Chris Martin.

The winners and losers alike can agree that the event was a massive success.