Brian Gottfried could not say when he felt the match beginning to slip away in the D.C. National Bank Classic at the Rock Creek courts yesterday.

For one set, it all seemed effortless and errorless. Then, Claudio Panatta began to get to all those shots that had eluded him, and kept the ball in play.

Gottfried, the No. 3 seed, started to make the errors. He missed too many volleys on returns at his feet and his backhand passing shots went awry. "My game dropped off noticeably and his picked up," Gottfried said, after losing, 0-6, 6-4, 6-4. "That's a bad combination."

There was no one point on which it turned, no one moment he could isolate as his undoing, perhaps because he had so many chances to make it right after it started to go wrong. He had a break point when Panatta served for the second set at 5-4, and four more in the eighth game of the third set.

Love-40. Gottfried needed the break desperately. But it wasn't to be. "He made two good shots and I missed a passing shot," Gottfried said.

Panatta, who is unseeded and ranked 112th in the world, saved those three break points and then gave him another. But Gottfried chipped a backhand return wide. Six more times they went to deuce. On the sixth game point, Panatta finally prevailed.

"Sometimes when you think you have the match in your hand, you have the toughest time getting the final point," Panatta said, shaking his head. "Finally, I made it."

The tournament, which has become the no-name classic, lost two seeded players to injuries before it began and lost two more yesterday: Gottfried, who is ranked 16th in the world, and Mel Purcell, who is ranked 25th.

Purcell, the No. 5 seed, lost to Mario Martinez, the No. 15 seed, 4-6, 7-6 (7-4), 6-1. Martinez, who lives in Potomac will play Panatta in the quarterfinals. Panatta is 23, the younger brother of Adriano, the 1976 Italian and French Open champion. "I'm not as good as he used to be," he said.

Though clay is his favorite surface, Panatta eliminated Jose-Luis Clerc in the first round of Wimbledon for the biggest victory of his career.

Clerc, the No. 1 seed, had a much easier time yesterday. He breezed by Derek Tarr of South Africa, 6-4, 6-2, in 1 hour 11 minutes. Tarr was pinned to the base line by Clerc's relentless and penetrating ground strokes.

Jimmy Arias, the No. 2 seed, needed only 1 hour 5 minutes to beat Dominique Bedel of France, 6-4, 6-1, whom he defeated in the final of the only Grand Prix tournament he has won. Arias even conceded a point to Bedel, the 13th seed, on a controversial call in the first game of the second set. The point, originally called for Arias, would have given him a break. His gallantry made it deuce instead.

"I didn't see the mark," he said. "I knew it wasn't the one four inches out. I figured I might as well be the nice guy for one time in my career.

Purcell struggled all day, even to stay on his feet. After 10 games, he was up a set but down physically. After 2 hours 2 minutes in the oppressive heat Thursday, he was depleted yesterday. Martinez must have sensed this. Purcell wilted; Martinez got stronger and smarter, making Purcell run and run, turning his quickness, which is his strength, against him.

On the fourth deuce point of the first game of the second set, Martinez, who had already saved three break points, hit a lovely backhand drop shot with so much spin it bounced back over the net. Purcell charged at full tilt, leaped over the net and into Martinez's arms.

"I hung on because I was about to fall down," Purcell said. "I was so tired by the time I got to the net. He deserved to win. He played me smart."

Purcell's forehand is his best weapon. Often, he runs around his backhand to hit inside-out forehand winners. In the first set, it was enough. But then, he had nothing left. After he fell into Martinez's arms, he lost three straight games. He got back into the set when Martinez served for it at 5-3 and was broken, hitting a looping forehand lob wide. Purcell had another chance--his best, he said--at 5-5, 30-30 on a second serve. He tried to put it away and failed.

With Martinez serving at 3-2 in the tie breaker, Purcell again had a chance on a second serve. He came in on it and was passed by a lovely backhand cross court that gave Martinez an edge he never lost.

Purcell said he thought players should get extra points on the computer for playing in Washington in July. Martinez comes from La Paz, Bolivia, but has lived in Potomac for two years. He says he likes everything about the area: the shopping, the movies, his girlfriend. But, mostly, he said, "I like the change of the four seasons."

Martinez broke in the first game of the third set. Purcell summoned enough energy to break back but did not have enough left to hold in the third game. He fell behind, 0-40, saved a break point, but was broken on a forehand cross-court return. He was never in the match again.

What was it he said to Martinez in the clinch? "He called me something," Martinez said, smiling sweetly. "But it was in a nice voice."