NEW YORK — Top-seeded Ana Ivanovic lost in one of the biggest upsets in tennis history today, stunned by 188th-ranked Julie Coin 6-3, 4-6, 6-3 in the second round of the U.S. Open.

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 winning another Grand Slam championship dashed.

Even after Ivanovic showed the effects of a bad thumb and struggled in the opening round, there was no way to see this coming.

Coin spent much of the year playing in minor league events, and the 25-year-old Frenchwoman nearly got knocked out of a qualifying event to merely make it into the Open.

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

"No," she said.

Not since 1967 had the No. 1 woman lost in the second round of the U.S. Open. That came when Maria Bueno drew a first-round bye and lost in the second round.

During the first four days at the U.S. Open, almost of the favorites had won. Mostly in romps, too.

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

Ivanovic seemed to regain her edge midway through third set. The French Open champ 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, and won 10 straight points to take control.

Ivanovic tried to hold off Coin in the final game, but it was too late. Coin won on her third match point — quite a result for someone playing in her first tour-level event.

Coin had tried to qualify for the Australian Open, French Open and Wimbledon and never made any of them.