BOSTON (AP) _ Antoine Walker hit a big 3-pointer, cupped his hand to his right ear as he ran downcourt and listened for the roars.

That sound has become louder since Jim O'Brien replaced Rick Pitino as coach, and fans who used to boo the hometown Celtics have found plenty to cheer about. Boston's 94-91 win over the Milwaukee Bucks on Wednesday night was its fifth straight at home.

``The atmosphere in the building now is great,'' said Walker, who led Boston with 36 points and 13 rebounds. ``We want to make the FleetCenter as intimidating as the old Garden used to be.''

The Celtics teams that played in Boston Garden were intimidating with players like Bob Cousy, Bill Russell and Larry Bird. But the current team is finding ways to win _ using persistent defense and focusing on every play down the stretch.

Under Pitino, the Celtics were 12-22. Under O'Brien, they're 10-5 and have climbed into the eighth and final Eastern Conference playoff spot.

Wednesday's win was especially impressive since the Bucks lead the Central Division with the NBA's second-highest scoring average. They also led 69-64 after three quarters, and Ray Allen got the first triple-double of his career _ 20 points, 10 rebounds and 11 assists.

``We were holding the ball too long,'' Bucks coach George Karl said. ``Passing never became part of our game.''

Milwaukee failed to score 100 points for only the fourth time in 20 games. And it hit just 36.8 percent of its shots and 16 of 25 free throws. Boston's Paul Pierce, who had 27 points, made 16 free throws in 19 attempts.

``I struggled from the field,'' said Pierce, who missed 17 of 22 shots, ``but I'm never going to lose confidence out there. I stayed aggressive and got to the foul line.''

Walker's 3-pointer with 4:31 left gave Boston an 82-78 lead and brought the fans out of their seats. But it was Pierce's 7-for-7 free-throw shooting in the last minute and Eric Williams' steal of Tim Thomas' inbounds pass with 13 seconds left that sealed the win.

Thomas scored 21 points, while Glenn Robinson had 18 points and 15 rebounds. And Milwaukee outrebounded Boston 62-46, with four players getting at least 10 rebounds.

But the Celtics were better in the fourth quarter, when the Bucks made just five shots and missed seven free throws.

``Sometimes we're going to make shots, sometimes not,'' Milwaukee's Ervin Johnson said, ``but it's defense that wins games.''

Allen's dunk cut Boston's lead to 89-88 with 17 seconds to go before Pierce hit two free throws, Williams stole Thomas' pass and Walker hit two more from the line to build the lead to five.

Thomas' 3-pointer made it 93-91 with 2.1 seconds left, but Robinson was called for fouling Pierce out of bounds, giving Boston one free throw and the ball.

Pierce hit the shot and the Celtics ran out the clock.

``Defense comes first. Offense comes second,'' Walker said. ``That's what's taken us over the top.''

Notes: Boston held an opponent under 100 points for the ninth time in 10 games. ... The Celtics trailed for the last 10 minutes of the third quarter and the first five of the fourth, finally going ahead for good, 79-78, on Pierce's three-point play with 5:12 left. ... Allen made his 331st consecutive start, most among active players. He's played in all 343 games since he was drafted by the Bucks. ... Walker had his 28th double-double in 48 games. ... Karl remained a win short of his 100th with the Bucks.