NEW YORK Twice former champion Serena Williams was pushed hard for the third successive match as she battled past Russian Vera Zvonareva 6-4 7-6 to reach the fourth round of the U.S. Open on Friday.
The eighth-seeded American, bidding for her ninth grand slam title, turned in another patchy performance and needed one hour, 59 minutes to set up a match with Wimbledon runner-up Marion Bartoli of France in the round-of-16.
"I was upset after the match. I didn't feel that I played the greatest at all," a somber Williams told reporters after getting past Zvonareva. "I actually felt like I didn't play well at all.
"But that's said and done. I'm moving on."
Zvonareva had not played since April because of a left wrist injury but matched Williams from the baseline until the American snatched the opening set with a service break in the last game.
The Russian, a quarter-finalist in 2003, led by a break early in the second set, but Williams fought back and won the second-set tiebreak 7-4 after storming out to a 6-1 lead.
Australian Open champion Williams, playing her first competitive matches since the quarter-finals at Wimbledon because of a thumb injury, looked sluggish and showed little exuberance on the court.
Williams' mood may also have been darkened by the umpire's directive early in the match that she put away notes she had taken with her to the court, as is her custom.
"He told me I couldn't use my notes. I was like, well, it's not like I'm Harry Potter, and my dad can magically gives me notes to read. It's something that I write myself.
"I'm happy I was able to come through," said Williams. "You just got to fight, hope to win. And that's what I did."
Williams was asked if she felt her game coming together.
"I don't think I've been practicing the greatest, so... hopefully I'm waiting for it to come together," Williams added without much conviction.
Williams said she needed to improve to beat 10th seed Bartoli, who lost to her sister, Venus Williams, in the Wimbledon final.
"I saw her play at Wimbledon. It's going to be a good match. She's doing really well. I'll have to be ready."