Former world number one Serena Williams continued her impressive return to form with a convincing 6-3 7-6 victory over Czech Lucie Hradecka in the first round of the Cincinnati Open on Tuesday.
Williams, fresh from clinching the Toronto Cup on Sunday, is looking for her third tournament win since coming back from an 11-month injury lay-off in June.
The American will next face the woman she beat in Sunday's final -- Australian Samantha Stosur -- in the second round.
Tenth-seeded Stosur brushed aside Eleni Daniilidou of Greece 6-3 6-1 in her opening match.
Williams looked in good form in the first set as she pounded her serve against the 49th-ranked Hradecka, who came into this week on a six-match losing streak.
However the American, who was 5-2 up in the second, struggled to finish off her opponent and showed some signs of tiredness before sealing victory in the tie-break.