In the aftermath of the Game 4 collapse, Celtics coach Doc Rivers admitted he made a mistake not playing Brandon Bass more down the stretch against a smaller 76ers lineup. Yet, Rivers still didn’t play Bass in the final minutes of the fourth quarter in Game 5, either.

That’s because Bass had already erupted for 18 of his playoff career-high 27 points in the third quarter, igniting a 101-85 blowout win that gave the Celtics a 3-2 lead heading back to Philadelphia for Game 6 on Wednesday.

Kevin Garnett (20 points, 6 rebounds), Paul Pierce (16 points), Rajon Rondo (13 points, 14 assists) and Greg Stiemsma (10 points) all reached double figures as well in the C’s victory.

WHAT WENT RIGHT

Breakout Bass: After exceeding 15 points in 18 games during the regular season, Bass had yet to eclipse that mark in the playoffs. And Rivers didn’t like it, imploring No Pass Bass to earn his nickname and take the open shot when it’s there. Bass responded in Game 5, scoring 18 of the C’s 28 points in the third quarter and helping turn a 50-47 halftime deficit into a 75-66 lead after 36 minutes of action. He had his new career playoff scoring high before the fourth quarter.

Stinkin’ Badger: After the Celtics introduced a steamboat whistle to announce Greg Stiemsma‘s entrance into Game 1, the Wisconsin native came into Monday’s game with two points on 1-of-3 shooting for the series. Without the whistle intro in Game 5, Stiemsma erupted for eight points on 4-of-4 shooting — in his first 5:46 of action. He made three straight baskets midway through the first quarter on his way to eight of the C’s 23 points in the opening 12 minutes.

Match game: Along with Garnett, who enjoyed another stellar playoff game in this Back to the Future postseason of his, and a dash of Ryan Hollins, Bass and Stiemsma helped neutralize Lavoy Allen and Thaddeus Young, who combined for 19 boards off the bench in Game 4. That number dropped to six between them in Monday night’s blowout victory.

WHAT WENT WRONG

Worst first: The Celtics came out lazy, and the Garden crowd reciprocated, sleepwalking through the first quarter. During one particularly painful stretch, the 76ers scored on eight straight possessions, including one trip down the floor when Stiemsma and Ray Allen watched as Jrue Holiday picked up a lose ball between them, dribbled out to the 3-point line and buried a triple to give the Sixers a four-point lead that felt like 14.

Holiday break: Speaking of Holiday (10 points, 7 assists), the 21-year-old 76ers point guard ran wild on the Celtics in the first half. He connected on four of his first five attempts, including 2-of-2 from beyond the arc. As a result, the absence of Avery Bradley (shoulder) meant Rondo had to carry the brunt of the load on both ends of the floor.

It’s a shame about Ray: And speaking of Bradley, his replacement — you know, that Allen guy — struggled on both ends of the floor. He started just 1-of-5 from the floor while Sixers counterpart Evan Turner continued to be a thorn in the C’s side this series, connecting on four of his first eight shots and collecting 10 rebounds for the game. Mickael Pietrus gave the Celtics some defensive stability at the shooting guard position in the second half, helping hold Turner to three points on 1-for-5 shooting over the final 24 minutes.