Petra Kvitova has lost her first match since returning to the WTA Tour following a six-week break due to exhaustion.

The 25-year-old went up against American Madison Brengle at the Porsche Tennis Grand Prix in Stuttgart, but she suffered a 6-3 7-6(2) defeat in the second round.

Kvitova lost serve early in the first set, and despite showing some fight by saving four break points in the sixth game, the Czech lost the opener.

Brengle kept the momentum flowing in her direction by going a break up instantly in the second set, but the set was forced into a tie-break after Kvitova grabbed a break of her own.

Despite the Wimbledon champion's effort, she was unable to push the contest into a third set and she lost the decider 7-2 in Germany.