Joe Mazzulla said all the right things. Asked before Tuesday’s game against the Bulls – which the Celtics needed to win by at least 23 points to have a chance to win their group in the In-Season Tournament – if he felt any obligation to win by a certain point differential, he was clear.

“Zero,” Mazzulla replied.

Mazzulla and the Celtics have continued to insist that their focus in these IST games is to win and create good habits first, and let the chips fall where they may in terms of making the tournament’s quarterfinals.

They got both.

Behind a big third-quarter surge, the Celtics did what they needed to do and emerged with a 124-97 victory – a 27-point margin – over the Bulls. Combined with the Nets’ 115-103 victory over the Raptors, the Celtics won Group C of the tournament and clinched a berth in the IST quarterfinals, though it didn’t get there without some late chaos.

The Celtics are expected to visit the Pacers next week in the IST quarterfinals, with the winner headed to Las Vegas for the semifinals.

This Celtics victory was rarely in doubt against the lowly Bulls. They led by 19 at halftime and they took a lead as large as 31 in the third quarter. At a certain point, Mazzulla started coaching with an eye on the point differential. The coaching staff was monitoring the Nets-Raptors game, with a Nets victory required for the C’s to win their group. Mazzulla insisted that the point differential was not a priority, but when the circumstances of the game and situation revealed that the quarterfinals were in reach, the priority shifted.

Some strange scenes unfolded in the fourth quarter because of the unique situation. With 7:34 remaining and the Celtics leading by 28, Mazzulla re-inserted his starters into a game that was well out of reach. Moments later, with the Celtics leading by 29, Mazzulla instructed his players to foul Bulls center Andre Drummond – an action known as “Hack-A-Drummond” because of his poor free-throw shooting. Fifteen seconds later, with the C’s up 32, they fouled Drummond again.

Drummond missed all four of his free throw attempts. Mazzulla later said he planned on apologizing to Drummond to explain to him why they were fouling him intentionally in a lopsided game.

In the midst of that crazy scene, Bulls coach Billy Donovan walked over to midcourt to talk to Mazzulla, but he wasn’t mad. Mazzulla said he was explaining the situation and the scenarios that were at play.

The Celtics starters stayed in the game until there was 1:52 remaining, when they led by 27, and they held on to win by the necessary margin.

Some other takeaways:

– Early on, at least, it looked like the Celtics were gunning for the winning margin of at least 23 points they needed to have a chance to make the In-Season Tournament quarterfinals, because of their shot selection. In the first quarter, they were shooting from deep at an even higher rate than usual, as they took 16 3-point attempts in the opening period. A whopping 15 of their first 18 shots from the field were from long distance.

The Celtics only took eight 3-point attempts in the first quarter, as they went inside more. Either way, they were still operating the right way within their offense with crisp ball movement. The C’s finished the fist half with 21 assists on 26 made field goals, which included a 13-for-24 clip from 3-point distance. Holiday and White combined to go 8-for-8 and 5-for-5 from three in the first half.

– Score another win for Celtics assistant Matt Reynolds, who is in charge of deciding whether or not the team makes a decision to challenge a call. With 5:34 left in the second quarter, Brown was whistled for a foul on a Zach LaVine layup. The call stunned Brown, who not only thought he had a clean block but thought the ball went off LaVine. He immediately signaled to Reynolds – who reviews plays quickly from an iPad in the second row – to challenge the call. The Celtics did and it was once again successful, as the C’s regained possession.

– Brown seems to be getting back into a rhythm offensively after an uneven start to the season. His best play this season has seemed to come with Kristaps Porzingis alongside him but even without him, he had one of his best games of the season Tuesday both scoring and playmaking as he finished with 30 points and six assists.