The Milwaukee Bucks gave the Philadelphia 76ers a lesson in patience, teamwork and aggressiveness tonight as they rolled to a 109-86 victory at Milwaukee Arena to force a deciding seventh game Sunday in their National Basketball Association Eastern Conference playoff semifinal.

That game will be played at the Spectrum in Philadelphia at 1:05.

The Bucks shot just 37 percent in the first half and trailed, 45-44, at intermission. But they dominated the second half on the outside shooting of Brian Winters, Bob Lanier and Quinn Buckner and the inside strength of Mickey and Marques Johnson. The Bucks outrebounded the 76ers, 55-29, on offense 24-11.

Mickey Johnson led the Bucks with 22 points, 12 rebounds, three steals and a blocked shot, but it was the Bucks' depth and the relentless pressure they put on the 76ers that took the toll.

Julius Erving led Philadlphia with 25 points, but the only other 76ers in double figures were Andrew Toney with 12 and Caldwell Jones with 11. The Bucks had all five starters and Winters in double figures.

The Bucks had a seven-point lead with 2:40 left in the first half, but Erving led a 12-4 rush that gave the 76ers their halftime lead. Erving had seven of the points and assisted on two.

A 9-2 spurt, with Mickey Johnson scoring six, gave the Bucks a six-point lead early in the third period. The 76ers made only one more charge at Milwaukee and that came after Toney scored eight straight points to get his team to within three with 2:28 left in the third quarter.

Winters made a long jumper, Sidney Moncreif made a free throw. Mickey Johnson grabbed an offensive rebound and scored to hike the Milwaukee lead back to eight and the Bucks gradually pulled away.

With the Sixers limited to one shot and getting beaten so badly under the defensive boards, their offensive was turned into Erving and Toney taking turns going one on one.

That was not the way to beat the bucks.

Philadelphia Coach Billy Cunningham became so frustrated at his team's ineffectiveness that, after it was called for a 24-second violation, screaming, "Dumb, dumb."

Margues Johnson did not play the fourth game of the series Wednesday in Phladelphia because of back spasms and the Bucks were concerned about how effective he would be tonight. Johnson started slowly, getting only three points in the first half, but finished with 15 points, 10 rebounds, three assists and three steals.

The Johnson that did the job tonight, however, was Mickey, the slender 6-foot-8 forward from Aurora (Ill.) College. With the 76ers concentrating more on stopping Lanier, who had 20 points and 11 rebounds, and Marques Johnson, Mickey Johnson always managed to end up around the basketball.

For the second straight game, the 76ers sent 7-1 Caldwell Jones to guard Marques Johnson and put Erving on Mickey Johnson. But Darryl Dawkins got into foul trouble early and Jones had to guard Lanier, making things easier for the Bucks.

"We didn't make any real changes for this game," Mcikey Johnson said "and we won't make any for Sunday's game. We want to force them into making the changes."