"It felt fitting, I guess," Williams, 30, said of playing Petkovic again. "It was a great way to start it all off."Williams began the match with two double-faults and she made a series of unforced errors, particularly off the forehand side.

    She wasted three match points in the final game and saved a break-back point before finally taking it when Petkovic went wide with a forehand.

    In other matches, third-seeded Victoria Azarenka beat Peng Shuai of China 6-4, 7-6 (2), while fifth-seeded Petra Kvitova recovered from a slow start to defeat Anastasija Sevastova of Latvia 5-7, 6-1, 6-3.

    Williams' sister Serena will make her return to action after nearly a year out against Tsvetana Pironkova on Tuesday. She could then face top-seeded Vera Zvonareva.（本文由在线英语听力室整理编辑）