As can happen in tennis, one risk that works can save the day. Today, one saved Hana Mandlikova.

She saved match point, saved the game, played a superb tie breaker and dominated the third set against West German teen-ager Steffi Graf. When it was over, Mandlikova had produced a remarkable 2-6, 7-6 (7-3), 6-1 victory to reach a semifinal match against Chris Evert Lloyd.

While the women were taking center stage on yet another cool, damp Parisian day, the men completed their fourth round, advancing some strange names into the quarterfinals. One was Andrei Chesnokov, the young Soviet who upset Mats Wilander on Saturday. He continued his string of success with a 6-4, 6-1, 4-6, 6-1 victory over Francisco Maciel, setting up a quarterfinal meeting with the only Frenchman left, Henri Leconte.

Leconte, who was two sets and two match points down Saturday against Casio Motta, learned his lesson and came out flying today. He romped past Horacio De La Pena, 6-1, 6-2, 6-1, in one of the most one-sided matches of the tournament.

The other winners on the men's side today were Boris Becker and Mikael Pernfors. Both worked hard and long to survive. Pernfors, a native Swede and two-time NCAA champion from Georgia, saved five set points in the third set and three in the fourth before upsetting 11th-seeded Martin Jaite, 6-1, 3-6, 7-6 (8-6), 7-6 (7-3). Becker trailed Emilio Sanchez, two sets to one, had to wait out a brief rain delay and then came back to win just before nightfall, 6-0, 4-6, 4-6, 6-4, 6-2.

Mandlikova's save of a match point came at a time when Graf seemed to be streaking toward victory. The roll that began 24 matches ago apparently was going to continue. Mandlikova had played good tennis, but not good enough. Graf had too much quickness, too strong a forehand, too much confidence.

And so they came to match point, 65 minutes after their French Open quarterfinal began this afternoon, and the crowd at Roland Garros Stadium was buzzing at the efficiency of Graf.

Graf went for a big first serve. She missed. Second serve. Mandlikova decided to chip a backhand return and come in. Graf lined up her forehand. Perhaps it was the sight of Mandlikova at the net. Perhaps it was that the moment came just a little too soon in her life. With victory one winner away, she unloaded a dud, a forehand that sailed way past the baseline.

Once Mandlikova had been spared, she went on a roll of her own, knocking off one winner after another in the last set. Graf, for once, looked like a 16-year-old girl. She was overmatched.

"Once she saved the match point, she started playing much better," Graf said. "I didn't think I was moving too well, but in the third set she hit a lot of good shots. On match point, I had to get the first serve in. I wasn't surprised when she attacked on the second, but I just hit a bad shot."

Mandlikova sighed. "I wasn't even thinking about the score most of the match," she said. "I was just trying to hang in there. For sure, though, I knew it was match point. I had to attack her. I had no choice."

Evert reached the semifinals for the 44th time in 45 tries in Grand Slam tournaments, coming back after a sloppy first set to beat Carling Bassett, 5-7, 6-2, 6-1. "I really struggled in the first set. I was sluggish," Evert said. "Once I got my game going in the second set, I thought I was much stronger than she was. I looked across the net and she looked tired. Once I was ahead, 2-0, in the second, I knew I would win the match."

In fact, both women's matches today turned radically. Evert, after double-faulting to lose the first set, hammered Bassett the rest of the way as Bassett struggled with leg cramps, a knee bruise and fatigue. "I was so tired after the first set," she said. "I had put everything I had into winning the first, and I was exhausted. I had to play shorter points, go for winners, and that hurt me."

For Becker, today's victory was especially satisfying since Sanchez had upset him at the Italian Open two weeks ago and looked ready to repeat. Sanchez is a classic clay-court player, a patient athlete who, Guillermo Vilas-style headband flying, runs down ball after ball.

Becker, whose biggest problem on clay is impatience, ran into that problem for a while this evening, going for winners on shots where hitting a winner was impossible. But after asking for a suspension of play because of the rain -- a move booed lustily by the crowd -- he settled down just in time, breaking Sanchez to take a 5-4 lead in the fourth set.

He then saved four break points, coming up with a big serve each time, and won the set with a neat backhand volley that Sanchez (naturally) ran down, only to watch a huge Becker overhead rocket past him for the set.

"The court was very wet and slippery, and we had played eight games in the rain," Becker said. "When I came back I felt pumped up the way I do at the start of a match. Maybe that's why I do well in interrupted matches."

Becker won three suspended matches at Wimbledon last year and has won two here this year. Once he had taken the fourth set, he was home free. The fifth was brief, Becker breaking at love in the third game.

The crowd, most of which stayed and chanted for play to continue during the 20-minute rain delay, seemed to sense Sanchez was finished. So did Becker. Attacking more and more, he quickly broke Sanchez again for a 4-1 lead and cruised from there.

"He's tough to play because he doesn't make mistakes," Becker said. "I just had to keep trying, even when it looked pretty bad for me."

Those words were almost identical to the ones uttered by Mandlikova after her victory. Many people here thought Graf would win this tournament, that the time would finally come when Evert and Martina Navratilova would give up the torch they have shared for 10 years.

Even fighting a cold, Graf certainly looked ready for that challenge today. Her forehand already may be the most dangerous weapon in women's tennis, and she kept pounding it into the corners. Even the graceful Mandlikova couldn't run everything down.

But after serving at only 44 percent in the first set, Mandlikova began to get stronger. She took a tumble chasing a ball in the opening game of the set, cutting her knee and jamming her right pinky badly enough that she thought for a moment it was broken. Bloodied but not beaten, she continued, struggling but not quitting, as she has at times in the past.

"Even when I was losing I was still fighting," Mandlikova said. "I wouldn't have felt that bad if I had lost, because she was just playing very good tennis. She was just nailing everything from the forehand side. I just hung on."

Mandlikova can do that now. Once, she just would have started spraying balls off the walls. Today, she never looked rattled. And when Mandlikova cracked two clean winners to reach set point in the tie breaker, it was clear that Graf was rattled. When she netted a forehand to end the set, she slammed a ball angrily into the clay.

"I think my experience helped me," Mandlikova said. "If she was older, she might not have gotten upset. I know more about playing a third set than she does. I think it helped me."

Something helped. Mandlikova broke Graf immediately, setting the break up with a gorgeous drop backhand, then watching her pump a forehand deep. Graf began missing. The whistling forehands were now carrying long and wide. Mandlikova stayed patient: chipping her backhand, using her forehand as a weapon. It was over quickly. Graf won 14 points.

The end came when Mandlikova waited patiently for an opening on her third match point before finally bringing Graf in with a short backhand chip. Graf lunged, lobbed and watched the ball sail long. As it did, Mandlikova screamed, "Yes!" wiped a little more blood from her knee and walked off very happy.

"It's a very good win for me," Mandlikova said. "It still doesn't compare with beating Martina or Chris, because they are two of the greatest ever. Steffi is very good and she will get much better, but she still hasn't won anything big."