Sam 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 next faces defending champion Kim Clijsters, whose fourth-round victory ended more than 13½ hours earlier — at 12:02 p.m. Sunday.

"She played first; I played last," Stosur said. "There's not much bigger difference."

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.