By JOE KAY

MASON, Ohio (AP) -- Rafael Nadal's 16-match winning streak fell against another teenager who knows him well.

The 19-year-old Spaniard wasted three match points while losing to Tomas Berdych 6-7 (4), 6-2, 7-6 (3) on Tuesday night, the first notable upset of the $2.45 million Cincinnati Masters.

The second-seeded Nadal was worn down from his first hard-court title. The French Open champion beat Andre Agassi in Montreal on Sunday for his tour-leading ninth ATP win of the year, and didn't have much time to get used to the conditions in Cincinnati. He came up one point short in a match that lasted 2 hours, 57 minutes.

"I don't have good luck in the match points,'' Nadal said.

Lleyton Hewitt shook off the effects of a severe stomach virus, and Russia's Marat Safin struggled with an aching knee while advancing in their opening matches Tuesday. Berdych's repeated escapes on a muggy night provided the day's best drama.

The 19-year-old Czech survived five break points to keep the third set knotted, then overcome three match points to send it to the tiebreaker, where Nadal double-faulted twice.

Berdych had beaten only one Top 10 player in his career -- he's now 2-8 against them -- but wasn't intimidated by an opponent who is the same age and needed three sets to beat him last month at Bastad.

"I've known him for so long,'' Berdych said. "I saw him when he was 12. He was in the same tournament. We know each other so well.''

The third-seeded Hewitt beat Igor Andreev 6-3, 6-4 on a muggy afternoon that tested his stamina. A week earlier, the Australian had to quit a first-round match in Montreal because of the stomach ailment -- the first time he's ever given up.

"I didn't eat for about four or five days,'' Hewitt said. "So it hit me pretty bad. I felt a little bit awkward the last few days just training, getting back into the routine of things again. I'm definitely a lot better than a week ago.''

Safin also got back onto the court after a much longer absence Tuesday. The fourth-seeded Safin hadn't played since Wimbledon because of a slightly torn ligament in his left knee.

It was better, but still painful.

"I took a risk to come back and play and prepare for the U.S. Open,'' Safin said. "I decided to try to play, to see if it gets better or if it gets worse.''

He opened his match against Jan Hernych with a double fault, and doubled faulted twice while losing the opening game. He eventually got rolling and pulled out a 7-6 (3), 6-4 win.

Safin didn't wear a brace or wrap on the troublesome knee. He moved better as the match went along.

"It's kind of difficult,'' Safin said. "It (the knee injury) is still in my head. When you feel some pain in some movements, you try to avoid those. After the first couple of games, I tried to forget about it and focus on the game.''

Steady rain delayed the day's opening matches by 2 hours, forcing organizers to scramble the schedule. Players who had practiced in 95-degree heat over the weekend were faced with much different conditions -- gloomy, thick air and temperatures in the 70s.

Three other seeded players lost their opening matches Tuesday after the long rain delay -- No. 8 Gaston Gaudio and No. 10 Mariano Puerta of Argentina, and No. 13 Thomas Johansson of Sweden.

"It's no fun waiting around to see when you're going to play, if the rain's going to stop,'' said Robby Ginepri, who beat Puerta 7-6 (2), 6-1. "I'm pretty thrilled that the day's now finished.''

Three of the tournament's top four players have advanced to the second round. No. 1 Roger Federer won his opening match Monday -- his first match since he won Wimbledon.

Agassi had to pull out of the tournament because his chronic back problem flared up, but hopes to be ready for the U.S. Open. Federer, Hewitt and Safin also are heading into the Open with less time on the court than they'd like -- not that Hewitt thinks it will matter to the favorite.

"Federer is in a class of his own,'' Hewitt said. "I don't think limited matches are going to affect him too much whatsoever. He's played enough big matches, and his record in finals against Top 10 players over the last two years really speaks for itself. I don't think it's really going to cause him a lot of havoc.''

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