After sweeping through his first two opponents, Lleyton Hewitt finally found a challenge at the Legg Mason Tennis Classic.

And it almost took the No. 2 seed out of the tournament.

As temperatures soared to more than 100 degrees at the William H.G. FitzGerald Tennis Center, Hewitt survived a nearly flawless match from Frenchman Cyril Saulnier to advance to the semifinals, where he'll meet Robby Ginepri today.

Top-seeded Andre Agassi didn't get quite the same test from Saulnier's countryman, Paul-Henri Mathieu, beating him in straight sets, 6-4, 6-4.

Hewitt and Saulnier matched winners through three grueling sets in the tournament's best match thus far, but the Australian prevailed in a thrilling third-set tiebreaker for a 6-3, 3-6, 7-6 (7-5) victory. Each player lost only a single service game in a battle that lasted 2 hours 20 minutes.

"He's a flashy kind of player, like most French guys are out there, he has all the shots in the book," said Hewitt, who hit 17 aces compared to Saulnier's 16. "He really made few unforced errors from the second and third set onwards."

As the second hour of play came to a close, the players held serve in the tiebreak through five points, with Hewitt leading 3-2. But Saulnier finally stumbled, and Hewitt took advantage, sending a backhand winner past his opponent into the open court. Six points later, Saulnier sent a forehand into the net, giving Hewitt the match and the trip to the semis.

"I'm playing well," Hewitt said. "I think today was an awkward sort of match because I just couldn't quite get my teeth into it after winning that first set."

The players put up almost identical statistics, with each winning exactly 50 percent of the total points and the Frenchman just a tad better in both total service points and total return points won.

Hewitt didn't so much win the match as simply outlast the seventh-seeded Saulnier. The Frenchman had the only three break chances in the opening game of the third set, but couldn't capitalize.

"He served extremely well and it was tough to get into many of his service games out there," Hewitt said. "I was just trying to take care of my service games and wait for an opportunity. If you get to a tiebreak, then it's anyone's match."

While Agassi built his career on his legendary return game, it's his serves that have kept him going during his run to his seventh straight semifinals at the Legg Mason.

Agassi advanced with five more aces yesterday, after smashing 12 in his quarterfinal. His serve has been broken just once here -- in the opening set of his first-round matchup with Paul Goldstein. Against Mathieu, Agassi didn't face a break point.

"It's a tough court to return on," Agassi said. "The ball really moves through the air, but then, when it hits, it sort of sits there. You end up leaning for serves, and then you have to put a full swing on it to get it to do anything. It's a weird feel. I think it's just overall harder on the returner right now."

Not nearly as good as he was on Thursday, when he dominated Kristian Pless, Agassi still was crafty enough to get by Mathieu, continuing his run of eight straight match wins that dates from his victory in Cincinnati two weeks ago.

While maintaining a calm, fluid stroke, Agassi seemed to rattle the 22-year-old, causing jerky movements, awkward swings and quite a few unforced errors.

Agassi got his first break in the opening set on Mathieu's third service game and took advantage. After the break, the 34-year-old served out the first set with an ace and then a service winner.

Agassi, while not flawless with his groundstrokes, appeared to be holding back throughout much of the early part of the match, simply waiting for Mathieu to begin making mistakes.

And Mathieu, who is 198th in the ATP rankings, obliged with multiple unforced errors.

After breaking Mathieu in the first game of the second set, Agassi's serve picked up. While he might have two matches left here, he is clearly looking ahead.

"So far I feel great," Agassi said. "I'm rising to the challenge of each guy and looking forward to the next one. . . . It's hard to ask for much more than what I've had now going into the [U.S.] Open. Last week was a great week and this week I'm feeling real comfortable out there. I have a lot of reasons, right now, to look forward to New York."

Andre Agassi storms into semifinals with a 6-4, 6-4 victory over Frenchman Paul-Henri Mathieu."It's hard to ask for much more than what I've had now going into the [U.S.] Open," said Andre Agassi, who made his 7th straight semifinal at the Legg Mason.