Top-seeded Brian S. Gottfried sailed and seventh-seeded tan Smith struggled in the second round of the $125,000 Volvo Classic yesterday at Smith Center, and the man they each call coach will not be available for consultation when they play each other tonight in the quarterfinals.

Dennis Ralston, the former U.S. Davis Cup captain, counts both players among his stable of world-class tennis talent, but he also has a strict rule. "If they play each other," Ralston said, "I don't say anything to them before or after the match. It's a difficult situation, but I have to remain neutral."

Mostly, however, Ralston remained happy yesterday as Smith came back from a sluggish first set to defeat Mike Cahill, 7-6, 6-1, and Gottfried, the defending champion is this affair, needed only 67 minutes to dispose of Phil Dent, 6-2, 6-1.

In other afternoon action, with only 300 people scattered in the stand, fourth-seeded Raul Ramirez defeated Gene Mayer, 6-3, 7-5, and advanced to another quarterfinal match against Tim Gullikson, a 6-4, 6-4 winner over veteran Tony Roche.

Ralston will be travelling the circuit for 20 weeks beginning in May, coaching Smith, Gottfried, Dick Stockton, Roscoe Tanner and Harold Solomon. This is a relatively new arrangement for the players, and for Ralston.

Ralston worked with Gottfried and Stockton at the World Cup last summer, and both asked him to accompany them to Wimbledon. "They liked the arrangement and it's worked out well for all of us." Ralston said.

"I work out of Mission Hills Country Club (in Palm Springs, Calif.) from October to April, and they'll all come out there to practice and work on their game and their conditioning," Ralston said. "I'm in touch with them all every week if I'm not out on the tour with them."

In Palm Springs, Ralston works on all aspects of each man's game - strategy, weakness, news shots - and has instituted a grueling conditioning program. "We do a lot of training, two-a-day practices," said Ralston. "I strongly believe in being in absolutely top physical shape. But these guys know that. They're all dedicated athletes, and they know what it takes to win out there."

Gottfried had not had a full-time coach before this season, and he is pleased with the results.

"It's good to have someone there seeing what happens to you in a match," he said. "Even today, I'm sure there are things Dennis saw that I wouldn't be able to know myself; my thinking at a certain point, that sort of thing.

"Last year, there were a few matches I lost and I really didn't know why. I thought I hit the ball well, but still I lost. A coach watches both guys; he gives you a better perspective. And that has to help."

Ralston had worked with Smith for years on a part-time basis when he captained the Davis Cup team from 1968 until 1975. "He knows my game so well it's like he's got a videotape machine of me in his head," said Smith.

"We've been working a lot on movement, trying to get me fit and quick on the court. I think my strokes are as good as anybody's in the game, but if you're not in position to hit the ball, what good does it do? We'll also talk strategy before and after a match. It's a Davis Cup-type of situation.

"When I was playing and he was captain, we'd go somewhere and work for a week and a half, just practicing. This arrangement gives us the same kind of opportunity to work on our games with someone who knows us well, and at the same time play in the tournaments."

Ralston and all his players are represented by Washington attorney Donald Dell, and, of course, the coach is paid for his services. "All of them are striving to be the best player in the world," Ralston said, "but they're all good friends, too.

"We try to have the sort of relationship where we're all in this together. They'll help each other out whenever they can. I don't know if anyone resents it. I've heard some players make comments like coaches are a waste of time. I think that's ridiculous."

"I know this: all the guys have the ability to be No. 1 in the world. On their records alone, they're just a fraction behind Borg, Connors and Vilas. And that makes them play harder."

Gottfried played hard at all the right moments yesterday. He broke Dent's first serve and was never seriously threatened thereafter, despite having a number of break points against him.

"No, the empty seats don't bother me," he said. "My whole life until recently was spent playing in front of my parents and my wife. Three people don't make a whole lot of noise."

Smith rallied after trailing, 3-0, agains Cahill, a young man with a cannon serve who had one set point in the first set before dropping the tie breaker, 7-4.

Smith, who said he had recovered completely from a spot of flu Tuesday, had difficulty with his serve, but he was strong enough to win the last five games of the second set for the victory.

In another second-round match, Manuel Orantes, the third seed, defeated Vijay Amritraj, 6-2, 6-1.