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 yesterday.

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 the stands. Ivanovic quickly gathered her gear and left the court, her hopes of another Grand Slam championship dashed.

"If you would ask if I'm playing like a No. 1, no," Ivanovic said. "Obviously, it was very hard."

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.

It just didn't add up, even to the 25-year-old Frenchwoman with a mathematics degree.

Asked whether she'd thought such a win was possible, Coin gave a simple answer.

"No," she said.

And when did she believe it might happen?

"I guess when it was over," she said, drawing a huge ovation from the crowd at Arthur Ashe Stadium.

If there was any suspicion that Coin was wavering, she steadied herself by winning 10 straight points in the third set. It was Ivanovic who looked jittery, hitting shots directly into the net or way out.

During the first four days at the US Open, most of the favorites had won. Handily, too, with Venus Williams leading the romps earlier in the day.

But when the Ivanovic-Coin match was moved from the smaller Louis Armstrong Stadium to the main Ashe stage, fans hardly knew what was in store.

Tentative at times, Ivanovic seemed to regain her edge midway through third set. The French Open champion led 40-0 in the fifth game and was about to break Coin's serve when suddenly the momentum shifted.

Coin came back to hold, starting her decisive streak.

Ivanovic tried to stave off Coin in the final game, but it was too late for the 20-year-old Serbian star. Coin won on her third match point _ quite a result for someone playing in her first tour-level event.

Coin had failed to qualify for the Australian Open, French Open and Wimbledon. And she certainly wasn't anything bankable going into this match _ she'd earned less than $100,000 lifetime as a pro, and was facing someone who'd won nearly $6 million.