Juan Martin del Potro and Serena Williams were each winners at the BNP Paribas Showdown at Madison Square Garden on Monday.

The exhibition was more personality than substance, as del Potro downed 11- time Grand Slam champion Rafael Nadal, 7-6 (7-4), 6-4, in an entertaining bout.

The undercard featured a matchup of the top two players on the women's side and a rematch of last year's U.S. Open final, with the outcome being the same as Williams earned a 6-4, 6-3 win over Victoria Azarenka.

The highlight of the night was an impromptu doubles matchup that saw comedic actor Ben Stiller join with Nadal and del Potro teaming with a middle school girl from the stands.

The girl wound up being a prodigy, showing her skills with a variety of shots, including a difficult overhand and a forehand winner she blew right past an overmatched Stiller.

The typically austere Azarenka also showed a playful side in the second set of her match when, after several unforced errors, she gave her racket to her friend, Redfoo of the pop group LMFAO, who was sitting courtside.

Redfoo served three faults before engaging in a rally with Williams he eventually lost. Azarenka came back and played left-handed quite serviceably for several points, but lost the set when things intensified.

Both the ATP World Tour and WTA will be in Indian Wells, Calif., later this week for the lucrative BNP Paribas Open, which serves as a Masters event for the men and Premier tournament for the women.