Paris ? Rafael Nadal was terrified.

Not because he was in the throes of a possible upset Saturday, a nearly 5-hour match against an unheralded Frenchman playing brilliantly and backed by 15,000 rowdy countrymen in the stands. Nope, much scarier than that: The defending French Open champion thought he was choking on a piece of banana, right there on center court. In the middle of a game. When he was serving for the third set.

So Nadal put the ball in his pocket, walked over to sit in his changeover chair, and told the chair umpire he needed help. It was the oddest of pauses, the sort of thing you might expect to see in a public park, not at a Grand Slam tournament.

In any event, Nadal managed to clear his throat and get past a tough test from the 29th-seeded Paul-Henri Mathieu, outlasting him 5-7, 6-4, 6-4, 6-4 to reach the fourth round and improve to 10-0 at Roland Garros.

“I was getting pretty nervous and a little frightened. It wasn’t that I couldn’t breathe, but I felt something strange,” said Nadal, who turned 20 on Saturday. “So I said, ‘Wow, I’m going to stop. I’m going to stop so that nothing happens, and we don’t have a tragedy here.’ And if it looked bad, I didn’t care.”

Defending champion Rafael Nadel celebrates his third-round victory in the French Open. Nadal defeated Paul-Henri Mathieu, 5-7, 6-4, 6-4, 6-4, Saturday in Paris.

The interruption only added to the theatrical nature of the match, which included an epic first set that lasted 1 hour, 33 minutes, a game in which Mathieu saved nine break points, and rally after rally of more than 20 strokes.

Nadal stretched his record winning streak on clay to 56 matches, and if that’s to become 57, he’ll have to beat two-time major champion Lleyton Hewitt for the first time. They meet in the fourth round Monday, because Hewitt beat No. 22 Dominik Hrbaty, 7-6 (5), 6-2, 6-2.

Players often eat bananas to help avoid cramping during lengthy matches, and Nadal seemed to be chomping on them at every changeover, including at 5-4 in the third set. One bite slipped into his throat during the first point of that game. He played one more point, then stopped. Sitting, he shook a banana peel, and pointed to his neck, anxiety in his eyes. A trainer came out and visited him, then a doctor, during the three-minute delay. Eventually OK, he finished the game in short order.

Because their match took so long, the one between No. 8 James Blake, the only American man left in the tournament, and No. 25 Gael Monfils, a 19-year-old Frenchman, was switched from center court to Court 1. They had split the first two sets when play was suspended because of darkness, and action will resume today.