Venus Williams struggled with her serve. She kept tugging at her dress. Just as big a nuisance was her opponent, Shahar Peer.
On a day when No. 2 Kim Clijsters cruised to her fourth-round win at the U.S. Open, third-seeded Williams never looked quite comfortable in her 7-6 (3), 6-3 victory over 16th-seeded Peer on the second straight windy day in Arthur Ashe Stadium.
Williams got only 48 percent of her first serves in. She faced six break points and lost three. She squandered five chances to wrap up the first set in a 22-point 12th game. As for the dress — a red "daytime" version of the black, sequined number she wore two nights previously — well, she spent much of the match tugging at it to keep it at barely high-thigh level.
It was all part of a strange-feeling victory in which the two-time champion looked more like someone who was trying to find her form — which she is after missing most of August with an injured left kneecap — than someone breezing her way through the draw.
Her next match is a quarterfinal against No. 6 Francesca Schiavone, who had few problems in a 6-3, 6-0 win over 20th-seeded Anastasia Pavlyuchenkova.
Serving intelligently and handling Williams' power, Peer was surprisingly game, even though she fell to 0-6 lifetime against Williams and has yet to win a set. Trailing 6-5 and serving to stay in the first set, Peer staved off five set points before finally winning a game that took more than 12 minutes.
But Williams overpowered her in the tiebreaker to wrap up a first set that took 1 hour, 8 minutes.
While Williams is the only American woman left in the draw, the men have a number of options. No. 20 Sam Querrey pulled off a mild third-round upset, defeating No. 14 Nicolas Almagro 6-3, 6-4, 6-4. No. 18 John Isner had a match later Sunday against 12th-seeded Russian Mikhail Youzhny. And No. 19 Mardy Fish plays his fourth-round match Monday against No. 3 Novak Djokovic.
Other men's winners Sunday included No. 10 David Ferrer, who beat fellow Spaniard Daniel Gimeno-Traver in straight sets, and No. 8 Fernando Verdasco, a four-set winner over 31st-seeded David Nalbandian. It took 39 minutes to compete the first five games of the Verdasco-Nalbandian match.
"I think mentally I was really strong, even like in the first set for (five) games, almost 40 minutes, I was there all the time," Verdasco said. "You know, I felt positive and really good and focused."
Back on the women's side, Clijsters put a quick end to Ana Ivanovic's run, winning her 18th straight match at Flushing Meadows with a 6-2, 6-1 wipeout of the former world No. 1.
Ivanovic, who fell to as low as No. 65 after a couple of injury-plagued years, has gotten back to No. 40 and was trying to move higher. She won three matches at the U.S. Open and was getting her biggest test — and opportunity — against the defending champion.
It wasn't much of a contest.
After regaining an early break to pull within 3-2 in the first, Ivanovic got overpowered, losing seven straight games to turn the match into a rout. Clijsters, moving as well as anyone in the tournament, used heavy, deep groundstrokes to pressure Ivanovic into 28 unforced errors. Looking like the more comfortable player, Clijsters fought through the wind and took command.
"She's playing with a lot more confidence," Clijsters said, in describing her mindset. "I can stay with her in the beginning of those first few games where she was playing really good tennis, if I could just stay with her and kind of just, make her doubt once in a while."
Trailing 4-1 in the second set, Ivanovic served a game that went seven deuces, but double-faulted to end the game. Eight points later, the match was over. It lasted 59 minutes. Ivanovic said she was nervous through much of it.
"I was on the big stage again," she said. "Lots of emotions came back and I just felt a little slow and just a little bit out of it."
Clijsters next faces the winner of a match scheduled for later Saturday between No. 5 Sam Stosur and No. 12 Elena Dementieva.
The Belgian won the U.S. Open in 2005, then was off the tour for 2½ years while she got married and had a baby. She returned to win it again in 2009 and is still waiting for her first challenge at this year's tournament.
Other than a 7-5 second set in her first-round match, Clijsters has not been tested as she heads into the second week. She has lost a total of 14 games in four matches in what is the first true defense of her U.S. Open title because she missed 2006.
"Coming here as a defending champion has been a new experience and something that kind of keeps it fresh," Clijsters said. "It's a nice experience. And tennis-wise, as well, I've felt that I've been improving every match."