PARIS — It's newsworthy enough when anyone manages to win a set against Rafael Nadal at any stage of the French Open — let alone two sets in the first round.

PARIS — It's newsworthy enough when anyone manages to win a set against Rafael Nadal at any stage of the French Open — let alone two sets in the first round.

So a buzz built at Roland Garros on Tuesday when unseeded American John Isner pulled ahead of five-time champion Nadal by unfurling his 6-foot-9 frame to pound serves at upward of 140 mph, pushing up to the net time after time for volleys, and generally making the Spaniard uncomfortable for stretches.

"Quite clearly," Nadal acknowledged later, "this is a match that I could have lost."

In the end, he did not. Stretched to five sets for the first time in 40 career French Open matches, Nadal came back to emerge with a 6-4, 6-7 (2), 6-7 (2), 6-2, 6-4 victory over Isner and reach the second round.

"Really, what it came down to is the way he played in the fourth and fifth sets," Isner said. "I haven't seen tennis like that, ever."

Despite Isner's efforts, Nadal's bid to tie Bjorn Borg's record of six championships at the clay-court Grand Slam remained alive.

It was the most riveting match of a day that featured reigning U.S. Open and Australian Open champion Kim Clijsters' first appearance at the French Open since 2006, a 6-2, 6-3 victory over Anastasiya Yakimova. Also advancing were Maria Sharapova, Li Na, Andy Murray, Robin Soderling and Sam Querrey.

Two seeded women lost: No. 20 Ana Ivanovic, the 2008 champion, was eliminated 7-6 (3), 0-6, 6-2 by Johanna Larsson of Sweden, while No. 22 Dominika Cibulkova of Slovakia was beaten 6-7 (10), 6-3, 6-2 by Vania King of the United States. No. 11 Nicolas Almagro departed with a five-set loss to Lukasz Kubot of Poland.