The speech Coach Doug Moe plans to give his San Antonio Spurs before tonight's National Basketball Association playoff game with the Philadelphia 76ers was written for him by the Washington Bullets Tuesday night.

"What happened to Washington at home should drill into our heads even more what can happen to you in this league," Moe said, referring to the Bullets' 107-103 loss to Atlanta. "No series is over until you win that last game. Just ask the Bullets. They wanted to go back to Atlanta about as much as we want to go back to Philadelphia."

The Spurs, with a commanding 3-1 lead, go for the series' clinching victory tonight at HemisFair Arena in their best-of-seven Eastern Conference semifinal series.

If a sixth game is necessary, it will be in Philadelphia Sunday.

The Spurs won the first two games of the series at home and split the next two at the Spectrum.

So far in this series, as they have all season long, the Spurs have relied on three men to do the bulk of the scoring-George Gervin, James Silas and Larry Kenon.

Gervin is averaging 29 points a game, Kenon 25.5 and Silas 22. The other Spurs run, rebound, set picks and blend in with the superstars.

"Everyone on this team just does what he does best," said Silas. "Guys who can't score don't try to. They do other things. As long as we continue to play like that, we'll be fine and we won't be going back to Philadelphia."

Now that Silas is healthy after missing most of the two previous seasons with a knee injury, he teams with the high scorer, Gervin, to give the Spurs what is perhaps the most explosive back court pair in the NBA.

Silas is more of an aggressive one-on-one player, while the smooth Gervin, who has been the league scoring champion the past two seasons, is deadly from 20 feet out and murderous from inside when he posts smaller defenders.

Kennon is a showman. He likes behind-the-back passes, between-the-legs dribbling and one-handed snatch re-bounds.

"I play for the people and anyone who sees me play has to appreciate that," he said. "My game is to get the ball off the board and push it up-court."

The 6-9 Kenon does play more like a guard than Gervin, partly because Gervin does not want to handle the ball any more than necessary.

The Spurs have little muscle up front except for Mark Olberding, who was ready to square off with Philadelphia's Darryl Dawkins in Game 4 Sunday.

Offensively, the Spurs are a run-and-gun team that led the NBA in fewest number of 24-second violations.

"We don't ever change our game plan," said Gervin. "We make other people change theirs."

The word around the NBA is that the Spurs are weak defensively. They normally do no play pressure defense, nor do they deny the ball much. They prefer to double-team the ball and go for steals instead of playing position defense.

That tradition was broken in last Sunday's game when Kenon was moved onto Erving. He overplayed him and forced him far outside. Erving missed 11 of 17 shots and scored only 15 points, and the 76ers were without any continuity.

The Spurs were 20th in the NBA in defense, but were first in offense and had a point differential of plus-5.2, the best in the NBA. CAPTION: Picture, George Gervin