MIAMI — Celtics guard Payton Pritchard often finds himself in the unusual position of being an essential reserve who is also called upon to finish off blowouts against another team’s second and third string.

The latest example came in Saturday’s 131-104 romp against the Knicks, when Pritchard played the first nine minutes of the fourth quarter and scored a team-high 11 points on 4-of-5 shooting. Pritchard said he embraces these opportunities, regardless of the stakes.

“I try to take advantage of those, because, you know, you can get stuck in a role sometimes and you can become a little bit robotic,” said Pritchard, who had 5 points, 10 rebounds, and 8 assists in the Celtics’ 103-85 win over the Heat on Monday. “I definitely get caught up in that at times, so I always got to remember to stay aggressive even if the role doesn’t call for that at times. So having those moments and feeling the flow of it again and attacking and getting in the paint, it definitely helps create that confidence going to the next game and just carrying that over.

“I know my team needs me to be aggressive, and that doesn’t mean shooting. That means making the right reads. If they’re not there, shoot the ball, but attack closeouts, create a two-on-one and make the right read.”

Pritchard was 3 for 3 from beyond the arc in the fourth quarter and had some particularly deep looks in the game. He said there are limits to his range, but they are quite a bit deeper than most would think.

“I’d say halfcourt, it’s like I’ve got to put a little more on it,” Pritchard said.

Injury report

Jaylen Brown (knee), Jrue Holiday (shoulder), and Torrey Craig (ankle) missed Monday’s game. Jayson Tatum (knee) was cleared to play after being listed as questionable.

The Heat were without All-Star guard Tyler Herro (illness) and forward Jaime Jaquez. But Andrew Wiggins, Kyle Anderson, and Davion Mitchell, who were acquired in last week’s deal that sent Jimmy Butler to the Warriors, were cleared to make their debuts.

Celtics coach Joe Mazzulla said there are some minor adjustments when preparing to face players on a new team.

“You just focus on some of the tendencies that they have, what they do as players,” Mazzulla said. “You kind of focus on that and the game will kind of tell where they’re at, how they’re being used. But really it’s just about their personnel tendencies and how they transfer over.”

No payoff for Riley

Heat president Pat Riley trademarked various versions of “three-peat” after the Lakers won their second consecutive NBA championship in 1989, when he coached the team. Los Angeles failed to win its third consecutive title the following year, but Riley eventually received royalties when teams such as the Bulls, Lakers, and Yankees went on to win three titles in a row.

So last week Heat coach Erik Spoelstra joked that the organization was pulling for the Chiefs to win their third consecutive Super Bowl, because perhaps Riley would throw a big party if Kansas City won. The Chiefs, of course, were walloped by the Eagles, 40-22.

“I really didn’t have a rooting interest last night,” Spoelstra said with a smile Monday. “I would have preferred it to have been a closer game.”