With 5 minutes, 8 seconds left in the second quarter, Pietrus suffered what Celtics officials called a "closed head injury" after a scary fall. No other details of the injury were known at press time.
Pietrus collided with Lou Williams while driving to the basket and landed on the court. He didn't hit his head, but he clutched it after he landed. There was a delay of approximately 15 minutes as Pietrus was put on a stretcher and transported to the hospital.
Pietrus was in the starting lineup in place of Ray Allen, who was out with an ankle injury.
The Sixers-Celtics rivalry is heightened when more is at stake, and winning the division is a big deal in the NBA because it ensures a team home court advantage in the first round of the playoffs.
This game figured to be much more competitive than the first meeting, a 103-71 Sixers home win on March 7. That was the biggest loss in the five years that Kevin Garnett, Allen, and Paul Pierce have been Celtics teammates.
As a sidelight, Friday's win, gave Collins a career 400-349 record in his 10 seasons as an NBA coach.
Collins talked before the game about how important it was for the Sixers to get off to a better start at home.
In their last two home games, losses to New York on Wednesday and Miami last Friday, the Sixers trailed by a combined 35 points at halftime.
Once again, the Sixers failed to get that desired quick start. They trailed by as many as 10 points in the first quarter and ended up down by 49-43 at halftime.
Spencer Hawes, coming off a 1-for-7 shooting performance in the 82-79 loss to the visiting New York Knicks, had eight points and eight rebounds in the first half for the Sixers.
Boston was led by Garnett, who had 14 points on 7 for 12 shooting. Point guard Rajon Rondo had 10 first-half assists.
Then came the third quarter, in which the Sixers shot 15 for 23 (65.2 percent) and hit their only three-pointer and all six foul shots. The Sixers didn't commit a turnover in the quarter while forcing five.
Elton Brand scored 14 points in the quarter, shooting 7 for 10, while Jrue Holiday added eight points.
Brand finished with 20 points.
"We make it tough on defenses when we hit shots and execute," he said.
Contact Marc Narducci at 856-779-3225, firstname.lastname@example.org, or on Twitter @sjnard.
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