Belgium’s Kim Clijsters kicked off her final season the best way she could Saturday, beating Maria Sharapova 6-3, 7-6 (8) in the final of the Champions Challenge.

In a duel between the last two U.S. Open champions, Clijsters rallied from 2-3 down to win the first set with an ace.

Sharapova, the world No. 2, missed a backhand to give Clijsters the break in the first game of the second set. The Russian used heavy hitting to break back in the fourth game to tie it at 2.

Clijsters’ ground strokes were more accurate, but she struggled with her serving. She double faulted on break point in the sixth game to give Sharapova a 4-2 lead.

At 6-6, Sharapova squandered a 4-1 lead in the tiebreaker with three consecutive errors.

Clijsters hit a backhand winner to save set point, a mishit backhand by Sharapova gave her match point, then the Belgian converted by charging the net and hitting a forehand volley winner.

Sharapova, who is using the Champions Challenge as her only preparation for the Australian Open, said she isn’t worried about her form.

“You’re never going to guarantee a win in every single match,” she said. “At some points in the match I felt a little bit flat. I’d like to get myself going. Other than that, I’m happy with the match I played here.”