A string of outstanding and improbable plays, several involving Julius Erving, in the closing minutes propelled the Philadelphia 76ers to a 107-103 victory over the Milwaukee Bucks today in Game 3 of their NBA Eastern Conference semifinal playoff series.

In falling behind, 2-1, in the best-of-seven series, the Bucks suffered an uncharacteristic flop in the late going.

Despite the absence of all-star guard Sidney Moncrief because of a torn muscle in his left foot, Milwaukee led, 99-96, with just more than a minute to play.

But because of Erving, that changed drastically within moments. With the 76ers struggling to beat the 24-second clock, Erving put up a shot from deep in the right corner that somehow found the backboard and fell through the hoop.

Rushing the ball into play, Milwaukee seemed to have a fast-break opportunity: forward Terry Cummings driving along the left base line against the 76ers' Clemon Johnson, a bigger, slower player. Just as Cummings, the Bucks' high scorer with 27 points, turned the corner, Johnson stole the ball. A lead pass for Erving seemed to be headed out of bounds, but Erving managed to retrieve it in the corner.

Immediately double-teamed, Erving began to lose his balance and fall out of bounds. Before he hit the floor, he whipped a pass to Bobby Jones, cutting beneath the basket. Jones scored on a reverse layup at the 22-second mark and was fouled. His free throw gave Philadelphia a 101-99 lead.

"Jones was supposed to be guarding Cummings," Johnson said of his critical steal. "But on transition, I ended up with him. He had a gleam in his eye when he saw me covering him. He had me at a disadvantage because of his quickness. I thought he would try and take me to the hole. I went for the steal. If I missed, I was going to foul him, but I batted it away."

Given the opportunity to tie the game or perhaps go ahead, the Bucks found that their nightmare continued. After they took a timeout to position the ball at midcourt, the inbounds pass from Paul Pressey bounced off Cummings' hands and into the back court for another turnover. That led to a pair of free throws by Philadelphia guard Sedale Threatt that iced the game.

Threatt came off the bench to score 20 points. The 76ers' Charles Barkley was the game's high scorer with 29 points and 13 rebounds, and guard Maurice Cheeks was brilliant with 16 points, 10 assists and eight rebounds.

"There were enough strange plays down the stretch to make a season's highlight or lowlight film," said 76ers Coach Matt Guokas. "The deeper you get into the playoffs, the more crazy plays you'll see."

That wouldn't seem to bode well for the Bucks, who will try to even the series here on Monday night, knowing full well that they could have been leading, 3-0. In Game 1, the Bucks, winners of seven straight Central Division titles, let an 18-point lead dissipate in the final quarter of a 118-112 loss. They won Game 2, 119-107.

"We're usually pretty good in those areas, like the final moments of a quarter," said Milwaukee Coach Don Nelson. "I really don't know why, but we haven't been this series."

In the second quarter today, the 76ers scored four points in the final 10 seconds. In the third, they outscored the Bucks, 8-4, in the final 1:46. In the fourth, Milwaukee had four of its 23 turnovers in the last 31 seconds. The Bucks didn't help matters by shooting an abysmal 15 for 29 from the free throw line.

"In that situation, you should be able to just go down and play and maintain a lead. We had the game," said Bucks center Randy Breuer. "We just missed the shots and had the turnovers and beat ourselves."

That's a feeling the 76ers have experienced themselves in the postseason, particularly in their 95-94 loss to the Washington Bullets in Game 1 of their first-round series, in which the Bullets scored 18 straight points in the final 3:49 to win.

"Now I think that game really helped our team," said Cheeks. "Now we know that a game isn't over until it's really over."

From Milwaukee's standpoint, the final moments marred what had been an outstanding series of moves and countermoves between Guokas and Nelson. Despite foul trouble and a lack of scoring from centers Breuer and Alton Lister, the Bucks were able to overcome a nine-point deficit late in the fourth quarter by using their guards, Pressey and Ricky Pierce, down low, exploiting a height advantage over Cheeks and Threatt.

The two scored 12 of the Bucks' first 18 points in the final period, spurring them to what seemed a comfortable lead until Erving made his improbable plays down the stretch.