WIMBLEDON, England -- Lleyton Hewitt grabbed a big lead in his Wimbledon quarterfinal, then wasted four match points.

	Tim Henman is trying to become the first British player to win the men's title since Fred Perry in 1936.

It would be nearly two hours until he would have another.

The No. 1-ranked Hewitt eventually overcame the first real challenge he's faced, outlasting No. 18 Sjeng Schalken 6-2, 6-2, 6-7 (5), 1-6, 7-5 Thursday to reach the semifinals.

The Australian next faces No. 4 Tim Henman, whose attempt to become Britain's first Wimbledon men's champion in 66 years was extended with a 6-3, 5-7, 6-4, 6-3 victory over 90th-ranked Andre Sa of Brazil.

Hewitt owns a 5-0 career record against Henman, a semifinalist for the fourth time in five years.

"Right now probably the toughest task in tennis is to beat Hewitt,'' said Henman, who has yet to face a seeded player. "He proves consistently why he's the best in the world.''

Friday's other semifinal pits 20-year-old David Nalbandian against 21-year-old Xavier Malisse. Neither had been to a Grand Slam quarterfinal before.

No. 27 Malisse, the first Belgian man since 1904 to get this far at Wimbledon, defeated 1996 champion Richard Krajicek 6-1, 4-6, 6-2, 3-6, 9-7. Krajicek, sidelined for 20 months after right elbow surgery, was the only past winner left in the field.

Nalbandian, playing his first grass-court tournament, beat Nicolas Lapentti of Ecuador 6-4, 6-4, 4-6, 4-6, 6-4 to become the first Argentine semifinalist at Wimbledon.

Hewitt -- never before a Wimbledon semifinalist -- and Schalken played a match seemingly suited to clay courts, both rooted at the baseline for rallies that sometimes lasted more than 30 strokes.

Hewitt failed to convert 11 break points in the third set, including those four match points at 6-5.

"I must have had about 500 break points in the third set,'' U.S. Open champion Hewitt said, "and wasn't able to take one.''

The first three match points were erased by poor returns from Hewitt -- one of the game's top returners -- and the fourth by an overhead from Schalken.

The momentum shifted to Schalken completely in the tiebreaker. With the Dutchman ahead 4-3, he hit a forehand that Hewitt watched land right beside him near the baseline.

The line judge made a late call, which Spanish chair umpire Javier Moreno-Perez overruled to put Schalken up 5-3. Hewitt threw his arms up and head back and yelled, "No!'' He argued to no avail.

Four points later, Hewitt put a forehand into the net to lose a set for the first time in the tournament.

"The match sort of turned. He got confident. He was not making the mistakes he made in the first 2½ sets,'' Hewitt said. "He started stepping it up. It turned into a dogfight.''

Schalken broke to go up 2-1 in the fifth set, but Hewitt broke right back. They exchanged breaks again right away.

Hewitt had to save break points at 4-4 and 5-5 -- pumping his fist, pounding his chest and shouting, "Come on!'' after winners.

"I pick out a lot of people in the crowd that I know. Everyone gets a little bit of a pump now and then,'' he said.

With Schalken serving at 6-5, Hewitt smacked a running forehand winner to set up his fifth match point -- oh-so-long after his fourth. Schalken then sent a forehand wide, ending it.

"I don't know what to say,'' Hewitt said. "I felt I should have been in the locker room a long time ago. In the end, he was playing the better tennis, but the fighting spirit came out of me.''

Schalken finished with 36 winners and 66 unforced errors. Hewitt had 22 winners, 43 errors.

Sa, who hadn't been past the second round of 10 previous majors, gave Henman yet another test.

"I dug my heels in and the crowd got me going and I began to turn it around,'' Henman said. "I had to keep fighting, but that's been the way pretty much through the whole of this tournament.''

If Henman beats Hewitt, he would be the first British man in a final since 1938.

"There's a lot of pressure on him to do well. He's made the semis so many times, and everyone expects so much of him here at Wimbledon,'' Hewitt said. "Everyone's been asking the question: 'When is he going to finally get through to the final and give himself a chance to win?'''