Marty Riessen defeated Bob Lutz, 6-4, 6-4, at Rock Creek Tennis Stadium yesterday to advance to the singles semifinals of the $40,000 Prudential-Bache Securities Grand Champions tournament.

"I've always played well here for some reason, even though clay has never been my best surface," said Riessen, a four-time doubles champion in the Washington Grand Prix event.

Lutz, the top money-winner on the circuit in 1984 and the leader after three tournaments this year, had trouble with his serve early.

"He was playing better on my serve than his," said Riessen. With Lutz getting behind 0-40 each time, Riessen broke in the third, fifth and seventh games. Lutz got two of those breaks back, but serving with a 5-4 lead, Riessen went up, 40-15, and took the set on an overhead smash.

In the second set, they traded breaks in the first two games, and were tied at 3 when Riessen broke Lutz. Each held serve to leave Riessen serving for the match at 5-4.

Lutz won the first point with a strong forehand. Riessen came back with four strong serves -- including service winners on the last three points -- to win the match and advance to a semifinal match today against Andrew Pattison, who defeated Tom Gorman, 6-4, 6-2, yesterday.

Cliff Richey gained a semifinal berth by defeating Colin Dibley, 5-7, 6-4, 6-4, in a crowd-pleasing match spiced with disputed calls. Richey broke Dibley in the seventh game of the third set, then went up, 5-3, on his own serve. Dibley saved two match points in the ninth game, which went to deuce four times before Richey's baseline return went just wide to give Dibley the game.

In the last quarterfinal, rain intervened with Jaime Fillol leading Dick Stockton, 5-4, in the first set. The match will resume at 10:30 this morning.

In doubles, Lutz and Ray Moore eliminated Charlie Pasarell and Eddie Dibbs, 6-3, 6-1. Riessen will have the opportunity to add to his Washington successes when he and Sherwood Stewart play Pattison and Richey this morning for the other semifinal berth.

Although both have done well in singles and doubles on the Grand Champions circuit, Riessen and Lutz had their greatest success on the Grand Prix circuit in doubles.

Lutz teamed with Stan Smith to win more doubles titles than any other Americans. They won the U.S. Open four times, made the Wimbledon final three times, and, in seven years of Davis Cup competition, lost only once.

Riessen has won the French Open and U.S. Open doubles titles.

What accounts for their amazing success in doubles?

"We're more percentage players," Riessen said. "We weren't power players. We relied on our quickness, and -- I don't want to say cleverness -- but . . . Instead of going for the winner in certain situations, we'll take one more shot to set up the winner. In singles, lots of times they'll hit the winner while you're setting it up."

Lutz has played doubles with Smith since 1965. "Back then, everyone played singles and doubles," he said. "You concentrated on singles until the doubles match and then you concentrated on that.

"Now, I can see why players are specializing. There's so much money in singles, I can see why they do it."