CLEVELAND -- A portion of the Cleveland Cavaliers' success this season came from Donovan Mitchell taking a step back, taking fewer shots and nurturing younger teammates into bigger roles.

But he's still the team's superstar and he took a turn in that calling Wednesday night, scoring 17 of his 30 points in the fourth quarter to hold off a vigorous Miami Heat comeback attempt as the Cavs took a 121-112 Game 2 victory. They'll carry a 2-0 series lead to Miami heading into Saturday's Game 3.

The Heat melted a 19-point Cavs lead down to just two with four minutes remaining. Mitchell entered the game and hit a floater and then back-to-back 3-pointers -- the second a 32-foot bomb -- to give the top-seeded Cavs a vital boost.

"I've worked really hard to be in those moments," Mitchell said. "You're fatigued or whatever, but you put your head down and get to the spots."

Mitchell averaged 24 points during the regular season, his fewest in five seasons. He averaged his fewest shots per game since he was a rookie in 2017-18. But in the two playoff games so far, he's verified his importance to the franchise with back-to-back 30-point games.

"I feel like when we need him he gives it, he knows the moment," Cavs coach Kenny Atkinson said. "He doesn't do it when we're up 10 or 15 (points). He'll wait and wait. I think that's the maturity level he's gotten to where he is in his career, understanding what the situation is, what the moment is."

It didn't look like such a moment would be required as the Cavs had a historic-shooting first half. They made 14 of their first 21 3-point tries and set an NBA playoff record by making 11 triples in the second quarter. Eight different Cavs made a 3 in the first half, with Mitchell assisting on five 3s in the second quarter alone.

But after being the No. 1 3-point percentage team over the first four-plus months of the season, the Cavs ranked just 17th after March 1, and that inconsistency showed in the second half. They made just 4-of-15 in the third quarter as the team tried a collective heat check. That dry spell opened the door for the Heat, the first No. 10 seed in the play-in tournament to make the playoffs, to show their relentlessness attributes.

Coach Erik Spoelstra moved guard Davion Mitchell into the starting lineup, and he backed up that decision by scoring 14 of his 18 points in the fourth quarter, when he was a catalyst at both ends. All-Star Tyler Herro scored 33 points, and Haywood Highsmith tried to balance out the Cavs' 3-point assault by making 5-of-6 3s on his way to 17 points.

But Mitchell made all four of his 3-pointers in the fourth quarter and the Heat were outscored 12-6 to close out the game.

"I love the fact that the game happened like this; I'd much rather this than win by 20," Mitchell said. "Especially going into an environment like we are in a few days (in Miami). We had to really find a way as a group."

Cavs forward Evan Mobley had 20 points and six rebounds and played key defense on Heat star Bam Adebayo, who had 14 rebounds but finished just 3-of-9 shooting. Thursday is potentially a huge day for Mobley, a finalist for the Defensive Player of the Year Award that will be announced that night. As part of the maximum contract extension he signed last fall, Mobley will collected a $45 million bonus over the next five years if he wins the award and triggers escalators in his contract that will take the guarantee from $224 million to $269 million.

"I mean it definitely was a goal of mine coming into this year, I put all the work in, so it's a big day," Mobley said. "But I'm trying to be as focused as I can on the playoffs."