Finally, in disgust, Andres Gomez took the ball from ball boy Charlie Sadoff and handed him his racket. "You play," the gesture said. "I can't."

The boy stood in the middle of Rock Creek Stadium last night, not knowing quite what to do. He kept offering Gomez the racket until finally, grudgingly, Gomez took it and went to receive as Jimmy Arias served for the match.

Arias, the No. 2 seed in the D.C. National Bank Classic, had just broken his serve, thanks to three infuriating volley errors. Gomez, the No. 6 seed, took refuge in humor. There was nothing else to do.

He had attacked and pressed and made some brilliant shots, forcing Arias to play his best tennis of the week. But, then, at the most critical moments, he began to make unforced errors. "As usual," he said, wryly.

And so, Arias, No. 11 in the world and a finalist last year, advanced to the semifinals, 7-5, 6-3.

He will play Eric Korita, an old friend and rival from Nick Bollettieri's Tennis Academy, who defeated Francesco Cancellotti, 6-2, 6-3, in a match delayed by rain for 58 minutes. Korita had four aces, two in the final game.

Like Gomez, top-seeded Jose-Luis Clerc plays an aggressive, attacking game on clay. "He goes for it," his coach, Patricio Rodriguez said. But he is far more consistent than Gomez. "He hits the ball hard and keeps it in play," Gomez said, wistfully.

Clerc, who has found his game after searching for it all spring, used those powerful, precise ground strokes to upend Pablo Arraya, the No. 9 seed, 6-1, 6-3. Clerc, a semifinalist here for five straight years, will play Mario Martinez, No. 15, in the semifinals tonight.

Although he was never broken in the match, Clerc said his concentration was broken by umpire Ken Slye. After breaking Arraya's serve in the first game of the second set, Slye warned him for delay of game, a code violation.

"Today, I feel very strange and nervous," Clerc, the No. 9 player in the world, said. "This guy (the umpire) gave me a lot of problems . . . I think the people are coming to see tennis not racing cars."

Clerc's nervousness did not show. He was in command from the start. Though he did not seem unduly impressed with his performance (he said he was operating at 70 percent of capacity), the timing on his ground strokes and the force behind them gave Arraya few openings.

Twice in the first game of the second set, with Clerc perched at the base line, Arraya tried to beat him with drop shots. Both times, Clerc scrambled for the get and hit sharply angled backhand cross court volleys for winners and break points.

The second time (his fourth break point in the game), Clerc broke with a forehand deep in the corner that forced a backhand error. He was in jeopardy only once in the match, serving at 4-3 in the second set. He fell behind, 0-40, but fought back to deuce with three strong serves that kept Arraya off balance and out of the match.

Martinez, a quarterfinalist here in 1981, the year Clerc won the tournament, outlasted Claudio Panatta, 7-6 (7-4), 3-6, 6-2, in a match that was long (2 hours and 36 minutes), close (five breaks) and lacking in drama.

They stayed back for the most part, trading ground strokes, distaining the net. While there were some lovely points, there were many long, base line rallies that ended with unforced errors.

Panatta tried to attack but Martinez used his backhand often and effectively, pulling him ever wider, stretching him. As the match wore on, Panatta wore out.

Martinez says his physique is his best asset. He swears that he has grown tired only once on the court during a three-set loss to Tomas Smid in Rome last year. He waited for his chance against Panatta.

Arias and Gomez played the best match of the day. For one hour and 13 minutes, they traded fearsome forehands, one shot seemingly more potent than the next. There was nothing languid about it. "Some people say our forehands are among the best in the world," said Gomez, who is ranked 29th in the world.

"Our games go together well," Arias said. "We were clubbing forehands. The trouble was he was getting his forehand first. I was doing most of the running."

Early on, Gomez applied most of the pressure, attacking whenever possible and often successfully. Arias may have been on the run but he also hit some wonderful running forehand winners down the line. Arias broke in the eighth game of the first set and served for the set at 5-3 but Gomez broke back.

He saved two set points to make it 5-all and Arias held for 6-5. Then, Gomez played his first sloppy game, two backhand errors and a glaringly bad forehand volley gave Arias the set, 7-5.

"The match turned around a couple of times," Arias said. "When it was 5-4 mine I thought I was in pretty good command. Then he saved two set points. Usually when you save two set points and tie it up, you have the momentum. But somehow I won the next two games and everything looked good."

But Gomez seized the advantage, breaking in the first game of the second set. A forehand winner down the line gave him break point. Arias protested that an earlier shot on the same point was long and was called for a code violation, as he slammed his racket to the ground and tossed a ball too close to the umpire's chair.

Arias broke back in the fourth game, to make it 2-all, thanks to two unforced errors. "Maybe I go for 20 winners and make 10 mistakes but I think it's the only way I can win," Gomez said.

They stayed even until Gomez served with Arias ahead 4-3. He netted a high backhand volley to give Arias his first of four break points. He mis-hit an overhead into the net to give him another, double faulted to give him a third, and missed an easy forehand cross court wide off a forehand passing shot to give him the fourth.

Gomez put his head in his hands. He served again and missed the same shot again. This time, he gave his racket away. "That was the final blow," Arias said.