The San Antonio Spurs made a tactical error. They thought they could outrun the Los Angeles Lakers.

"We're deeper than they are, and I really felt we could run with them," said Spurs Coach Stan Albeck. "But they've just been unreal."

The Spurs got the split they wanted at the Forum in the first two games of the series, but were stunned at home with defeats Friday and Sunday. They trail in the best-of-seven Western Conference championship series, 3-1.

The series will be resumed tonight at the Forum (WDVM-TV-9 at 11:30).

The 76ers also lead the Milwaukee Bucks, 3-1, in the Eastern Conference championship series, which will be resumed tonight in Philadelphia (USA cable, 8).

"We prefer a fast-tempo game, but we can't just let them (the Lakers) run wild," said Albeck. "We have to find a way to slow them down."

The Lakers have averaged 118.5 points a game against the Spurs.

"When we can get a team to run with us, we feel things are definitely in our favor," said Lakers Coach Pat Riley. "We've been able to run and we've gotten more than we expected from Bob (McAdoo), and that's been the difference."

McAdoo incurred a dislocated toe late in the season and missed the last month of the regular season and the entire playoff series against the Portland Trail Blazers, which the Lakers won in five games. But with each game of the San Antonio series, McAdoo has performed better. He made five of eight shots and scored 14 points Sunday in the Lakers' 129-121 victory.

"It's still sore at times, and my wind still isn't good, but at least I can play," said McAdoo.

If the Lakers-Spurs series is a shooter's delight, the Bucks and 76ers have been playing physical, defensive games. The 76ers have averaged 99 points a game, and only one game has gone into overtime.

Only a 100-94 victory Sunday in Milwaukee, with 5-foot-8 Charlie Criss and 6-11 Bob Lanier leading the way, prevented the Bucks' being swept in four games.

"We're still in a big hole," said Coach Don Nelson. "But we'll approach the game the same way we've approached all the others. We'll play hard and hope for the best."

Nelson said he is undecided whether to start Criss in place of Brian Winters, who is 6-4.

Paul Pressey started the first two games, but Nelson went to Winters in the last two. Criss played most of the time Sunday, however, and may have earned a starting spot.

One of the most effective Bucks has been Junior Bridgeman, who at 6-5 has played shooting guard and both forward positions in the series. But he sprained his right ankle in Sunday's game and it's uncertain how effective he will be tonight. It was the third time Bridgeman has sprained the ankle this season.

He scored 22 points as a reserve in the first game, but made only one of 12 shots in the second, when he started in place of Alton Lister at power forward.

Nelson stayed with him in the third game and Bridgeman responded with 24 points. He had made seven of nine shots when he had to leave Sunday's game with the ankle sprain. He tried to return, but couldn't.

Philadelphia Coach Billy Cunningham said he doesn't think the series is over "just because we have a 3-1 lead.

"Milwaukee could have won any of the three games they lost if they had gotten the breaks at the end," he said. "That's why every single game is so important. We wanted to win in four--not to embarrass the Bucks or send any messages to the Lakers, but just to win it. In the playoffs, you have to go into every single game like it's the last one."

The 76ers' Julius Erving said he wants to win Game 5 in grand fashion.

"It would be something that could carry us into the finals on a high note," he said. "It's important we get this thing over with because of the likelihood L.A. winds up its series."

If the 76ers and Lakers win tonight, the best-of-seven championship series will begin Sunday at the Spectrum in Philadelphia.