NEW YORK, April 10: Serena Williams's comeback stalled when she suffered a surprise 6-2 6-3 defeat by Russian Nadia Petrova in the quarterfinals of the Amelia Island championship on Friday.

Williams, who returned to competition after an eight-month injury lay-off to win the Nasdaq-100 Open last week, committed 42 unforced errors and failed to convert any of her 10 break-point opportunities at the $585,000 event in Florida.

Seventh seed Petrova capitalised on the rustiness of the former world number one to triumph in one hour 17 minutes and set up a semi-final with Lindsay Davenport.

Fourth seed Davenport made light work of finishing off her delayed third-round match from Thursday night, taking two games to beat Australian Alicia Molik 6-4 7-5.

The American then returned to oust Argentine Paola Suarez 6-4 6-1 in the quarterfinals.

Williams's defeat means the anticipated first meeting of the year with world number one Justine Henin-Hardenne will have to wait. The two players were scheduled to clash in the final.

The Belgian kept up her end of the bargain, overcoming Russian eighth seed Vera Zvonareva 6-4 6-3.

But Henin-Hardenne was far from comfortable, saving five break points in the first set.

She will meet third seed Amelie Mauresmo in Saturday's other semifinal after the Frenchwoman beat Italian 10th seed Silvia Farina Elia 6-4 6-3.

Results (quarterfinals):

Nadia Petrova (Russia) bt Serena Williams (U.S.) 6-2 6-3; Lindsay Davenport (U.S.) bt Paola Suarez (Argentina) 6-4 6-1; Justine Henin-Hardenne (Belgium) bt Vera Zvonareva (Russia) 6-4 6-3; Amelie Mauresmo (France) bt Silvia Farina Elia (Italy) 6-4 6-3

Third round: Lindsay Davenport (U.S.) bt Alicia Molik (Australia) 6-4 7-5-Reuters