Samantha Stosur saved four match points in a thrilling third set as she fought back to beat Russian Elena Dementieva 6-3 2-6 7-6 and reach the quarter-finals of the US Open in the early hours of Monday morning.
The fifth-seeded Australian won the climactic tiebreaker 7-2 to end the titanic, two-hour 38-minute encounter at 1:35 am (0535 GMT) in the latest-ending women's match ever staged at the US Open.
"That's definitely one of the most exciting matches I've ever played," Stosur told reporters. "The atmosphere out there was just awesome. I think we both played a great match."
The third set produced the best tennis of the women's tournament so far, with French Open finalist Stosur saving one match point when 12th seed Dementieva served at 5-3 and three more on her own serve in the next game.
The see-saw struggle saw both players raise their games in the final set, ripping groundstrokes with abandon and going for the lines.
In the end it was Stosur who held her nerve best, drawing errors from the usually steady Russian and clinching the decider on two forehand errors from the Olympic champion, who was runner-up at the US Open in 2004.
The women's match ended the night programme on center court, following a men's third-round match won by 12th-seeded Russian Mikhail Youzhny over American John Isner in four sets.
"It's tough," Dementieva said. "We were waiting for a long time before we went on the court.
"It was probably one of the latest matches I ever played in my life. It was really difficult to stay focused. We had ups and downs all the time, both of us, during the match."
Stosur seemed to fall out of synch in the second set, losing her serve all four times and spraying unforced errors. The Australian lost serve again in the second game of the third set to concede her fifth successive break and fall behind 3-0. She got back on serve with a break in the fifth game but Dementieva broke again to take a 5-3 lead.
That is when Stosur produced her most courageous tennis.
"I think the main thing is you want to play a tough point," said Stosur, who also saved four match points in winning a match last week in New Haven, and who saved a match point to beat Serena Williams at the French Open.
"If you get the opportunity to step in and go for a winner, of course do it. But you just want to make them earn it." Stosur had never before got past the second round at Flushing Meadows.
"I think the last year and half I've been playing much better and really found my confidence and belief," she said. "So to come here and get my best result ever is great."
The victory lifted Stosur into a quarter-final showdown against second-seeded defending champion Kim Clijsters. "I think she's won 18 matches in a row here," Stosur said of the Belgian, who also won in 2005 before her temporary retirement. "It's not going to be easy, but I'll give it my best."