BOSTON -- The Boston Celtics trounced the Philadelphia 76ers 120-87 in game five of their eastern conference first-round series on Friday as Paul Pierce scored a playoff career-high 46 points to overshadow Allen Iverson.

In a western conference decider, the San Antonio Spurs proved too strong for the seattle supersonics as they recorded an easy 101-78 victory to advance 3-2.

Pierce led Boston to its first postseason series win since 1992 by making 10-of-13 shots in the first half as he notched up a massive 29 points.

He fell one point short of Boston's franchise record for points in a half -- a mark held by John Havlicek and Larry Bird.

"I was in a groove and the guys did an extra good job of finding me in situations to put the ball in the hole," Pierce said. "We shared the basketball, that was the key. We don't mind passing up shots to get another guy an open shot."

The Celtics swingman had 10 points in a 15-4 run in the second quarter that gave Boston the lead for good, 54-43, with 3:20 left in the half. He bookended the spurt with 3-pointers.

Philadelphia's Iverson, the reigning league MVP, scored 20 of his 31 points in the first half but simply could not keep up with Pierce's torrid pace.

"That's the way this thing goes," Iverson said. "You play every game like its your last but sometimes that's just not enough and that was the case tonight."

A 3-pointer by Iverson at the buzzer pulled Philadelphia within 77-67 after three quarters.

But Boston used a 13-4 spurt to take a 97-79 lead with just over six minutes left.

The Celtics continued to pour it on and made nine of their 19 3-pointers in the fourth quarter, including several in the final minutes.

Boston outscored Philadelphia, 43-20 in the fourth.

"It was a wonderful experience to be able to, in the last two minutes, have the game in hand and kind of soak up the atmosphere," said Boston coach Jim O'Brien, a Philadelphia native who grew up rooting against the Celtics. "We played one heck of a basketball game."

Boston will visit second-seeded Detroit on Sunday for game one of their eastern conference semifinal series.

Towering Duncan

In San Antonio, Texas, Tim Duncan collected 23 points, nine rebounds and seven blocks as the Spurs used stifling defense in the first half to ease past Seattle supersonics in game five of their first-round series.

San Antonio will visit the Los Angeles lakers on Sunday in the opener of the conference semifinals. -------------------------------------------------- -----