he 76ers' impressive roll through the National Basketball Association playoffs came to a halt tonight, at least temporarily.

The Milwaukee Bucks, behind 27 points from center Bob Lanier and the phenomenal outside shooting of guard Brian Winters, closed the 76ers' Eastern Conference semifinal series lead to three games to two with a 110-98 upset in the Spectrum before 16,668.

The 76ers remain one victory away from meeting the rival Celtics--who eliminated the Bullets in Boston tonight--in the conference final. This series continues in Milwaukee with Game 6 Friday night.

The Bucks, who lost the first two games here last week, outscored the 76ers, 12-0, during a three-minute span of the fourth quarter and avoided being eliminated.

Philadelphia led, 77-72, with 1:35 remaining in the third period. But Winters, who scored 23 points, made a three-point shot with four seconds remaining in the quarter to tie the score at 79. Milwaukee took the lead for good, 84-83, on a three-point play by Lanier, the 34-year-old, gimpy-kneed center playing his 12th season.

Philadelphia closed to 89-87 after Julius Erving, who had 28 points, made two free throws with 8:13 left in the game, but Winters, after a turnover by Erving, made a short jumper for a 91-87 lead and started Milwaukee on its 12-0 spurt that ended with Sidney Moncrief's jumper and a 101-87 lead.

The 76ers made three three-point shots to pull to 103-93, and could have come closer. But 6-foot-11 center Darryl Dawkins, after blocking Lanier's shot, tried to dribble down the middle of the court and lost the ball. Milwaukee forward Alton Lister capitalized with a slam dunk to end Philadelphia's comeback.

The Bucks are used to getting superb performances from Winters and Moncrief (both made eight of 14 shots), but Lanier, who had been averaging 12.5 points the first four games of this series, was a most refreshing bonus.

"I'm not surprised by Bob's performance," said Dawkins, who spent the game being shoved around and outmaneuvered by Lanier. "He might not do that all the time now, but he's been around for 12 years. You know it's in him."

Lanier, playing down his offensive performance, said, "I don't feel great yet. If we win in Milwaukee Friday, I'll feel great. There was a lot of pressure on us tonight. Just about everybody had counted us out."

With good reason. Philadelphia came into this contest looking for its sixth victory in seven playoff games. The 76ers shot 56 percent against Milwaukee in the first four games, exhibiting a sometimes ferocious blend of inside and outside scoring.

But tonight the 76ers chose to attack from the outside. Guard Andrew Toney made eight of 20 shots, almost all of which came from 15 feet or farther.

Dawkins had 11 points, with three of his five baskets coming on fadeaway jumpers. "If you take Bob Lanier down low," he explained, "he'll just push you back out and they (the officials) won't call the foul. So I decided to try something different this time."

Whatever the reason, the 76ers' outside game wasn't enough. They shot just 49 percent and went stone cold midway through the fourth quarter when Milwaukee went on its spurt.