NEW YORK - Top-ranked Ana Ivanovic suffered one of the biggest upsets in tennis history when she was stunned by 188th-ranked Julie Coin of France 6-3, 4-6, 6-3 in the second round of the US Open on Thursday.

Ana Ivanovic of Serbia returns a shot to Julie Coin of France during their match at the US Open tennis tournament at Flushing Meadows in New York, August 28, 2008. [Agencies]

Never before in the Open era that began in 1968 had the No. 1 woman lost this early in the tournament.

Coin screamed when Ivanovic's last shot sailed out, then hopped for joy and hit an extra ball high into Arthur Ashe Stadium. Ivanovic quickly gathered her gear and left the court, her hopes of another Grand Slam championship dashed.

"Obviously, if you would ask me at the moment if I'm playing like a No. 1, probably not," Ivanovic said. "It's very frustrating because I know I can play so much better."

Even after Ivanovic struggled in the first round while coming back from an injured thumb, there was no way to see this coming.

Coin spent much of the year playing in minor events and nearly got knocked out of Open qualifying. The 25-year-old Frenchwoman recently played so poorly she thought about giving up the sport and relying on her mathematics degree.

"I was thinking, 'Am I really made to play tennis?"' she said.

Still, Coin couldn't have figured on it. Asked whether she'd thought such a win was possible, she gave a direct, honest answer.

"No," she said.

And when did she believe it might happen?

"I guess when it was over," she told the crowd, drawing a huge ovation.

If there was any suspicion that Coin was wavering, she steadied herself by rallying in the third set. It was Ivanovic who looked jittery, hitting shots directly into the net or way out.

Top-seeded Rafael Nadal avoided a similar fate on the men's side, beating American qualifier Ryler De Heart 6-1, 6-2, 6-4.

Nadal joined Venus and Serena Williams, James Blake, David Ferrer, Andy Murray and Dinara Safina in moving into the third round. No. 14 Ivo Karlovic posted the stat of the day while beating Florent Serra of France in straight sets. He finished ahead in aces 42-0.

The Ivanovic-Coin match was originally scheduled for the smaller Louis Armstrong Stadium, but was moved to the main Ashe stage to give the crowd a treat. The fans hardly knew what really was in store.