It used to be easy to overlook Johnny Moore, who played a unglamorous supporting role to San Antonio Spurs teammates George Gervin, Artis Gilmore and Mike Mitchell.

Not anymore.

After Moore's record-breaking game against the Denver Nuggets in the Western Conference semifinal playoff, the rest of the National Basketball Association is prepared. The Spurs won the series, 4-1, with a 145-105 victory Wednesday night.

"We were planning to let Moore shoot all he wanted, but not after the way he took Denver apart," said Los Angeles Coach Pat Riley, whose Lakers face the Spurs in the best-of-seven conference final beginning Sunday at the Forum.

"The person you would use to double-team Ice (Gervin) or Artis is Moore's man," said Riley. "Denver tried that and look what happened."

Moore, a 6-foot-3 third-year guard from the University of Texas, played like Oscar Robertson the entire series. He averaged 27.2 points, 14.2 assists and shot 60 percent.

His 71 assists set a playoff record for a five-game series and the 20 assists he had in Game 2 were a single-game playoff record.

Moore made 11 of 16 shots and had 24 points and 17 assists in the first game, a 152-133 rout by the Spurs. He scored a career-high 39 points, including all nine of San Antonio's in the overtime, in a 127-126 victory in Game 3. He had 20 points and 13 assists in only 29 minutes in the series clincher Wednesday.

The assists are no fluke, but not since he scored 68 points in a game in sixth grade has Moore shot as well as he did against the Nuggets.

"You never lose it," he said.

Moore led the NBA in assists in the 1981-82 season with 9.6 a game and was second to Magic Johnson of the Lakers this season with 9.8. He also was third in steals, with 2.52. But he averaged only 12.2 points and shot 47 percent in the regular season. So the Nuggets let Moore have uncontested 15-foot jump shots, a mistake.

"What else could we do, let Ice score 60?" asked Denver Coach Doug Moe.

"I've always looked to do whatever I could to help us win," said Moore. "Denver dared me to shoot. To score I have to shoot, and if I miss, I can't worry about it. When I was a rookie, I always thought that if I did miss, I'd get pulled out."

Moore almost never became an NBA rookie. He was drafted in the second round by the Seattle SuperSonics in 1979 but, in a prearranged deal, his rights went to the Spurs. He was cut before the season started, went back to Austin, Tex., and worked as a graduate assistant for the Longhorns. "And got down on myself."

He went back to the Spurs' camp as a free agent the following season and impressed Coach Stan Albeck enough to earn a job. He played in all 82 games and became the only nonstarter in the league to lead his team in both assists and steals. Moore became a starter two seasons ago and averaged more assists (9.6) than he did points (9.4).

He was a training camp holdout this season, then signed a three-year contract that pays him $90,000 this year and next and about $110,000 in the 1984-85 season.

Moore still plays out of control at times and loses his man on defense more often than Albeck would like. Nevertheless, at age 25, he has established himself as one of the most productive point guards in the league.

"Johnny may turn out to be the one the Lakers don't have an answer for," said Albeck.