The acquisitions resulted in a pair of trips to the NBA Finals, one culminating in a championship; two Eastern Conference championships, and five consecutive Atlantic Division crowns.
However, Allen and Garnett are unrestricted free agents this summer and one or both may not return next season.
"You hear a lot about 'This could be the last time,' " Sixers forward Elton Brand said Friday. "You never know. You never know what's going to happen if that's true. But it would be a great feat for us to beat them, with the Philly-Boston rivalry over the years. Why not us, if it can happen?"
Waiting for Lou
Lou Williams has yet to enjoy one of his typical breakout games in this series, but he's received plenty of respect from the Celtics defenders.
"[Rajon] Rondo was guarding him the other night and Rondo was wanting to help off a little bit and Doc [Rivers] was yelling for him to stay on Lou," Sixers coach Doug Collins said.
Williams, who led the team in scoring (14.9 points per game), is averaging 10.8 points in this series on 35.3 percent shooting, including just 4 for 18 from beyond the arc.
Sixers guard Evan Turner is averaging 8.7 rebounds this series and a team-high 7.5 in the Sixers' 12 postseason games. According to the Sixers, the 7.5 average is highest of any guard in the postseason.
The End, Part 2
With the Sixers down three games to two heading into Wednesday's Game 6, guard Jrue Holiday termed it "the end of the world."
So now that the Sixers have forced a deciding matchup following Wednesday's 82-75 win, Holiday was asked what he would call Game 7.
"End of the world II," he replied.
Celtics guard Avery Bradley, one of the top defensive players in the league, had season-ending shoulder surgery on Friday. Celtics coach Doc Rivers made the announcement before practice.
Staff writer Marc Narducci contributed to this article.