Todd Martin upset third-seeded Andre Agassi and top-seeded Jim Courier saved a match point for the second consecutive day before advancing Friday at the $780,000 indoor tournament at Memphis, Tenn.
Martin defeated Agassi, 6-1, 7-6 (7-4), after Courier had squeaked past Jonathan Stark, 6-7 (5-7), 6-3, 7-5, in the quarterfinals.
In the other quarterfinals, second-seeded Michael Chang easily defeated No. 9 Andre Chesnokov, 6-4, 6-0, and No. 6 Amos Mansdorf beat Dave Randall, 6-2, 6-2.
Martin took control in the tiebreaker against Agassi, going ahead, 5-4, on a passing shot and adding two quick points for the match.
Stark led, 5-4, in the final set against Courier and had a match point at 40-30, but Courier broke his serve when Stark hit a passing shot long. Courier then held serve and put away Stark with an ace.
"I just missed a few close balls there," Stark said. "I guess that's why he's No. 1. He found a way to win."
Courier was pleased with his comeback in the final set.
"This time last year, I was being up match point and losing matches, so it's a good feeling," he said.
Winning the Australian Open the last week of January left him with little time to prepare for this week's tournament, Courier said.
"I'm quite willing to trade the win in Australia for not being prepared here," he said.
Martina Navratilova maintained her mastery over Zina Garrison-Jackson with a 6-2, 6-1 victory in the quarterfinals of the Chicago Slims tournament.
It was Navratilova's 32nd victory over Garrison-Jackson in 33 matches.
Navratilova said she was hitting the ball better than she has in a long time.
"I was guessing on Zina's serve," she said. "You can do that if your opponent is not serving too hard. And, on top of that, I hit winners. In fact, I haven't hit so many winners in a long time."
Second-seeded Navratilova, seeking her 13th Chicago Slims title, will face Katerina Maleeva in a semifinal today. Maleeva, seeded fourth here, defeated Pam Shriver, 4-6, 6-4, 6-3.
In the other semifinal, top-seeded Monica Seles meets third-seeded Mary Joe Fernandez, who rallied to defeat 15-year-old Iva Majoli, 4-6, 6-1, 6-2.
Second-seeded Boris Becker, using explosive serves and powerful returns, trounced eighth-seeded Michael Stich, 6-2, 6-2, in an all-German quarterfinal of an indoor tournament in Milan, Italy.
Becker defeated his former Davis Cup teammate in 80 minutes.
In the other quarterfinals, Wally Masur, an unseeded Australian, defeated Frenchman Arnaud Boetsch, 7-5, 6-2; Petr Korda, the third-seeded Czech, beat Magnus Larsson of Sweden, 7-5, 6-4, and Sergi Bruguera of Spain eliminated Omar Camporese, the defending champion, 6-2, 1-6, 6-2.