Siebel Open

Andre Agassi survived a match point to continue his unbeaten run in 2003 and edge out Vladimir Voltchkov 6-7 7-6 6-1.

The Australian Open champion has yet to lose this year but looked on course for his first slip-up before recovering to win the two-and-a-half hour contest.

Afterwards Agassi said: "In my opinion, if he plays like that he should be ranked a lot higher.

"If tonight is his standard, it's one of the largest forehands I've ever faced."

Agassi now meets fellow countryman James Blake in the semi-finals. Blake beat Russia's Nikolay Davydenko 7-5 6-2 in the night's other match.

Blake gained the upper hand when he last met Agassi in Washington last summer, but insisted his opponent would prove a tougher obstacle six months on.

He said: "I've got my work cut out for me. He's playing as well as anyone in the world, if not a whole level better. It'll be fun and I've got nothing to lose."

Earlier in the day, America's Justin Gimelstob defeated Dane Kenneth Carlsen 6-3 6-4, while sixth seed Davide Sanguinetti knocked out Vincent Spadea.

Open 13

Swiss player Roger Federer advanced to the semi-finals of the Open 13 with a 6-4 4-6 6-4 win on Friday over Raemon Sluiter of the Netherlands.

Top-seed Federer is the only seeded player still in the running at the Marseille tournament.

Federer, who struggled to win, said he was starting to feel tired after playing in the Davis Cup in Switzerland last week.

I don't want to take any risks Nicolas Escude

"It was a lot tighter than last week at the Davis Cup in Arnhem, where I won very easily," he said.

On Saturday, Federer, ranked sixth, will play Karol Kucera of Slovakia, who beat Belgium's Olivier Rochus 6-3 6-3 in the quarter-finals.

France's Nicolas Escude will also play in the semi-finals after beating countryman Rodolphe Cadart 7-5 6-3 - although he suffered an injury along the way.

Escude had to be treated on the side of the court for a pain in his thigh before winning through.

He will review the situation with the ATP's doctors and has hinted he may not play in the doubles semi-finals on Saturday.

"I don't want to take any risks," said Escude.

"I know too much about this kind of little injury which can spoil your season if you let it get worse."

He will play Jonas Bjorkman of Sweden, who beat Dominik Hrbaty of Slovakia 7-6 6-4.

Bjorkman said he thought Saturday's match against Escude would be close with both having a similar attacking style.

"My confidence is good, and I'm taking all the risks," the Swede said.

Bellsouth Open

Former world number one Marcelo Rios, attempting to win an ATP tournament in his native Chile for the first time, reached the semi-finals of the Bellsouth Open on Friday.

Third seed Rios, whose last ATP title was in Hong Kong in 2001, beat Argentina's Agustin Calleri, the fifth seed, 6-4 7-6.

He will face either top-seed Gaston Gaudio of Argentina or Spain's Felix Mantilla in the semi-finals on Saturday.

"I'm still a little bit nervous but very determined," said the 27-year-old.