Unseeded Jimmy Arias, Horst Skoff and Ulf Stenlund upset seeded opponents at Monaco Friday to join fourth-seeded Mats Wilander in the semifinals of the $513,000 Monte Carlo Open.
Skoff, 18, of Austria, defeated fifth-seeded Andres Gomez of Ecuador, 7-5, 2-6, 6-4; Arias, 22, of Jericho, N.Y., advanced when seventh-seeded Kent Carlsson of Sweden, trailing, 0-6, 2-2, had to retire. Carlsson said he had a stomach ailment and suffered from dizzy spells.
Only hours earlier, he had completed a third-round victory over Argentina's Guillermo Vilas that had been suspended Thursday night by darkness.
Stenlund, 20, of Sweden, had to survive three match points before beating ninth-seeded Martin Jaite of Argentina, 2-6, 6-0, 7-6. Stenlund had defeated second-seeded Stefan Edberg in the second round.
Wilander, 22, of Sweden, earned a 6-1, 6-3 victory over Andrei Chesnokov. Wilander, the top-seeded player left after Edberg, Boris Becker of West Germany and Yannick Noah of France were eliminated in the second round, had lost to Chesnokov in the third round of last year's French Open but vowed "that won't happen again."
Friday, Wilander remained at the base line, engaging in long points, and controlled the 1-hour, 43-minute match.
"Against Chesnokov, you have to play like that," Wilander said. "Maybe it's a bit boring to watch. It's even a bit boring for me, but you have to wait for just the right shot before you go to the net.
"I think at the French Open, I went in a bit too early. I was more patient today."
Second-seeded Hana Mandlikova of Czechoslovakia outlasted fifth-seeded Gabriela Sabatini of Argentina, 7-5, 6-4, to reach the semifinals of a $150,000 Virginia Slims tournament at Houston.
Also advancing were top-seeded Martina Navratilova, third-seeded Chris Evert and fourth-seeded Zina Garrison. Navratilova beat sixth-seeded Lori McNeil, 6-1, 6-2; Evert defeated Kate Gompert, 6-3, 6-3, and Garrison ousted seventh-seeded Raffaela Reggi of Italy, 6-1, 6-0.
Navratilova will meet Garrison today, and Mandlikova will play Evert.