Rafael Nadal of Spain celebrates his victory against John Isner of the US during the French Open tennis tournament at the Roland Garros stadium in Paris May 24, 2011. [Photo/Agencies]

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.

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So a buzz built at Roland Garros on Tuesday when unseeded American John Isner pulled ahead of five-time champion Nadal by pounding serves, 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."