On a Sunday afternoon in which Kim Clijsters cruised to victory at the U.S. Open, third-seeded Williams never looked quite comfortable in hers. She defeated the 16th-seeded Peer 7-6 (3), 6-3 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.
"No," she said when asked if the dress bothered her. "The only thing that bothered me was when I didn't win the point, I think. That was it."
Williams likely will need to play better to get past Schiavone after a match 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.
"We always have had very competitive matches, so I know it's not going to be something I just walk through when I play against her," Williams said of the matchup against Peer. "I have to stay focused and ready to take every point or else she will. It was a good challenge."
Serving intelligently and handling Williams' power, Peer was surprisingly game, even though she fell to 0-6 lifetime in the matchup 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 an opening set that took 1 hour, 8 minutes.
"It's not new that I'm trying to win and fighting for every ball and hanging in there every point," Peer said. "But I do think it can give me more for the future, because every time I played Venus I had tough time and she was always kind of killing me every match."
Second-seeded Clijsters put a quick end to Ana Ivanovic's nice run at Flushing Meadows, winning her 18th straight U.S. Open match 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 going against Ivanovic. "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 closed with a double fault. 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 No. 5 Samantha Stosur.
Stosur won the latest-finishing women's match in U.S. Open history, erasing four match points and coming back to beat 2004 runner-up Elena Dementieva 6-3, 2-6, 7-6 (2) in the fourth round.
There were 15 service breaks in the 2-hour, 38-minute match that officially ended at 1:35 a.m. Monday, when Stosur converted her second match point.
"I was trying to fight till the end. Just feel disappointed the way I was playing the match points. I was not aggressive enough," Dementieva said. "But was really difficult to push yourself forward all the time -- because I was feeling, like, a little bit sleepy."
Who could blame her? The previous record for a U.S. Open women's match came in 1987, when Gabriela Sabatini and Beverly Bowes finished at 1:30 a.m. The latest finish at the tournament is 2:26 a.m., for a match between Mats Wilander and Mikael Pernfors in 1993.
"That's definitely one of the most exciting matches I've ever played. The atmosphere out there was awesome," 2010 French Open runner-up Stosur said. "I dug deep and never gave up and made her work for it."
Stosur and Dementieva, a two-time major finalist, started shortly before 11 p.m. because they followed the four-set men's match between John Isner and Mikhail Youzhny that opened the Sunday night session in Arthur Ashe Stadium and went 3 hours, 18 minutes.
Women used to begin night sessions in Ashe until last year, when the U.S. Tennis Association began occasionally flipping the order.
"Well, it was difficult to play. We were waiting for a long time before we went on the court," Dementieva said. "It's never easy to play that late. So we don't get used to it."
The fifth-seeded Stosur is the first Australian woman to reach the U.S. Open quarterfinals since Wendy Turnbull lost in that round in 1986.
Stosur never before had been past the second round at Flushing Meadows.
"It's a nice change," she said.
Playing high-risk, high-reward tennis against the 12th-seeded Dementieva, Stosur produced far more winners, 35-19, but also more unforced errors, 58-38.
"I think we both played a great match. Went for it and gave it our best," Stosur said. "To have a match like that here is just fantastic."
Dementieva reached the 2004 final at Flushing Meadows and the French Open. This U.S. Open represented her return to Grand Slam tennis after missing Wimbledon because of left calf injury; before that, she played in 46 consecutive major tournaments.
Dementieva held her first match point at 1:03 a.m., serving at 5-3, 40-30. But the Russian ended a nine-stroke exchange by pushing a forehand wide. Stosur then earned two break points and converted the second when Dementieva missed another forehand.
That got Stosur to 5-4, but she double-faulted at 30-all to set up a second match point, which Dementieva wasted by sailing a backhand long. Two more match points came in that game, and Stosur saved both, managing to hold serve for 5-all.
Stosur broke for the seventh time to go ahead 6-5 when Dementieva missed a forehand wide. Given a chance to serve out the victory, Stosur didn't make things easy on herself, putting a backhand into the net to give Dementieva a break point.
When an 18-stroke exchange closed with Dementieva netting a backhand, they were at deuce. Stosur hit a service winner at 111 mph to earn her first match point, then let that opportunity escape with a backhand of her own into the net.
Stosur controlled the deciding tiebreaker, though, taking the first three points and last three.
Information from The Associated Press was used in this report.