Playoff Forecast: Lakers Win in 4 : First-round series: Los Angeles graced with Magic Johnson and best record in NBA. In East, Pistons are expected to dispose of Pacers in three.

The Detroit Pistons, who ended the Lakers’ hopes of becoming the first team since 1966 to win as many as three NBA titles in succession, begin their own repeat bid tonight. The Pistons (59-23), with the best record in the Eastern Conference, play host to the Indiana Pacers in the best-of-5 series.

Other first-round series starting tonight are New York at Boston and Cleveland at Philadelphia in the East, and Denver at San Antonio and Dallas at Portland in the West.

Friday’s openers have Houston at the Lakers and Phoenix at Utah in the West, Milwaukee at Chicago in the East.

Only two franchises have won consecutive NBA titles--the Celtics and the Minneapolis-Los Angeles Lakers. Minneapolis won in 1949-50 and from 1952-54, and Los Angeles won in 1987-88.

The Celtics won eight in a row from 1959-66 and two straight in 1968-69.

Outlook and predicted outcome of the eight first-round series:

WESTERN CONFERENCE

No. 1 Lakers vs. No. 8 Houston--This could be tougher than anyone thought. The Rockets didn’t squeeze into the playoffs on the final day, but Akeem Olajuwon could dominate inside and Sleepy Floyd has shown signs of awakening from a season-long scoring slump, averaging 24.8 in his final four games. In addition, Houston is 2-0 against the Lakers in previous playoff series, handing them their only Western Conference losses in the 1980s. Los Angeles, however, has Magic Johnson and the best record in the NBA. Lakers in 4.

No. 2 San Antonio vs. No. 7 Denver--The Spurs are on a roll, winning their last seven games and overtaking Utah for their first Midwest Division title since 1983. The Nuggets won 6 of 10 games in April to reach the playoffs after three consecutive losing months. Look for David Robinson and Terry Cummings to dominate inside, but this series could turn sour for San Antonio if young guards Rod Strickland and Willie Anderson get playoff jitters against veterans Fat Lever and Michael Adams. Spurs in 4.

No. 3 Portland vs. No. 6 Dallas--The Trail Blazers tied Detroit for the second-best record in the NBA, and Portland swept the Mavericks in the regular season and handed them their two worst defeats. And the Trail Blazers won’t take anything for granted since they haven’t won a playoff series since 1985. Trail Blazers in 3.

No. 4 Utah vs. No. 5 Phoenix--The Jazz finished slowly, losing the Midwest Division lead to San Antonio on the final day and holding on to fourth in the conference only because the Suns lost to San Antonio. The Suns are healthy again after injuries to Jeff Hornacek and Dan Majerle. Suns in 4.

EASTERN CONFERENCE

No. 1 Detroit vs. No. 8 Indiana--The Pistons won 25 of 26 games in February and March, then finished the season 8-8, including 3-4 with Joe Dumars out with a broken hand. Even with Dumars back, Detroit looks ripe for an upset, but not against the Pacers, in the playoffs for only the third time in 14 years. Pistons in 3.

No. 2 Philadelphia vs No. 7 Cleveland--The Cavs look stronger than a seventh seed, winning their last six games after an uphill climb to playoff contention. Home court advantage and a Charles Barkley focused on winning rather than fighting save the 76ers. 76ers in 5.

No. 3 Chicago vs. No. 6 Milwaukee--The playoff-tested Bucks always seem to give fits to everyone, but point machine Ricky Pierce has been battling injuries, so they have no one to counter Michael Jordan. Bulls in 4.

No. 4 Boston vs. No. 5 New York--The Knicks have won six of 17 games without injured rebounding ace Charles Oakley, expected to play against the Celtics. But New York was struggling even before Oakley broke his left hand, and the Celtics haven’t lost to the Knicks at Boston Garden since 1984, which is appropriate since Boston has been playing like the perennial Eastern Conference finalists of the mid-80s. Celtics in 3.