Top-seeded Pete Sampras, surviving seven break points, defeated Australian Wally Masur, 7-5, 6-2, in the quarterfinals of the Manchester grass-court tournament Thursday at Manchester, England.
Goran Ivanisevic also advanced but was close to being defaulted before completing a 7-5, 6-3 victory over Arne Thoms of Germany.
Ivanisevic, a 19-year-old from Yugoslavia, received two warnings for code violations.
Ivanisevic was given his first warning in the ninth game after throwing his racket from the baseline to the umpire's chair.
Umpire Steve Ullrich issued the second warning in the third game of the second set for an audible obscenity and took away a point that cost Ivanisevic a game.
Another warning would have cost Ivanisevic the match.
"It was bad because I was swearing in English and if I'd sworn in my own language no one would have understood," Ivanisevic said. "It was a mistake."
He explained that he was upset at coming close to breaking his opponent's serve without managing to succeed.
At Eastbourne, England, Martina Navratilova, Arantxa Sanchez Vicario and Mary Joe Fernandez breezed into the semifinals of the Pilkington grass-court tournament.
Navratilova defeated Heather Ludloff, 6-1, 6-1; Sanchez Vicario beat Pam Shriver, 6-0, 6-1, and Fernandez defeated Yayuk Basuki of Indonesia, 6-2, 6-1.
Fourth-seeded Jana Novotna of Czechoslovakia was upset, 7-6, 6-4, by doubles partner Gigi Fernandez.
The top-seeded Navratilova, seeking her 10th Eastbourne championship and her 156th singles title, has lost only six games in her four victories this week.
Ludloff, a qualifier ranked 254th, has won only two matches all year.
Shriver, a grass-court specialist trying to come back from a shoulder operation, was down 6-0, 5-0, and had to save two match points before winning the 12th game. She raised her arms in mock triumph.
"I think that's probably the happiest I've ever been to win a game," she said. "Very few times in my life have I been losing like that."
Navratilova faces Mary Joe Fernandez and Sanchez Vicario will play Gigi Fernandez in the semifinals today.