The visiting Spurs will be looking for a ninth straight win Wednesday night in their only meeting of the season with the Celtics, who are trying to bolster their Atlantic Division lead with a ninth consecutive home victory.
Even though Allen has missed the last six games with a sore right ankle, Boston (30-22) has won five in a row overall to leapfrog Philadelphia for first place. The obvious highlight of that run was Sunday's 91-72 win over Miami, which shot a season-worst 34.8 percent in its most lopsided defeat of 2011-12.
The Celtics made a defensive statement while beginning a three-game stretch against elite competition. They visit Chicago on Thursday.
"We know we can play with the best," said Paul Pierce, who had 23 points -- his seventh straight game with at least 20. "It feels great. The crowd is behind you. You're executing. You're not turning the ball over. You're rebounding. That's the type of game we have to play."
They'll have to do it again with the Spurs (37-14) in town. San Antonio won for the 25th time in 30 games Tuesday, cruising past Cleveland 125-90.
It was also the Spurs' 14th win in 16 road games and 13th victory in their last 14 against Eastern Conference opponents. Coach Gregg Popovich's team moved within two games of West-leading Oklahoma City with Tim Duncan, Tony Parker and Manu Ginobili each playing less than half the game.
"Obviously, we're on a back-to-back and we got a little rest for the second game," Duncan said. "Perfect scenario? Pretty close."
Parker logged just 23 minutes and had 19 points on 9-of-12 shooting -- his best percentage this season and the fourth time in five games he's made more than half his shots.
He'll form an enticing point guard matchup with Rajon Rondo, who compiled 16 points, 14 assists and 11 rebounds Sunday for his fifth triple-double of the season. He's the only player in the league with more than one, and he's notched double figures in assists in 13 straight contests.
Backcourt mate Avery Bradley's production has been more surprising. Starting the last five games in place of Allen, the second-year guard has averaged 14.6 points on 52.8 percent shooting.
Allen practiced fully Tuesday and, barring a setback, is expected to return against the Spurs. But Bradley's solid play -- especially on the defensive end -- has sparked a debate about how the minutes should be split up down the stretch.
Coach Doc Rivers, though, confirmed Allen will regain his starting spot, and he's not worried about Bradley's transition back to a reserve role.
"I think he'll be great," Rivers told the Celtics' official website about Bradley. "We're going to try to sub guys a little differently to keep the combinations the same."
A seemingly rejuvenated Kevin Garnett has also been a big reason Boston is 8-0 at home and 15-5 overall since the All-Star break. Garnett is averaging 17.3 points and 8.6 rebounds in that stretch.
The Celtics have gone 6-2 against San Antonio since acquiring Allen and Garnett in 2007, including two wins last season. Rondo had a triple-double -- including 23 assists, not to mention six steals -- in a 105-103 win Jan. 5, 2011, the last time the Spurs visited Boston.