After losing the first three games of the Eastern Conference finals, the Boston Celtics didn't look like a team ready to flash some dominance.

But after winning the past two games by an average of 15 points, the Celtics are very much alive. They will seek to tie the best-of-seven series at threevictories apiece with the Heat on Saturday when the teams play Game 6 in Miami.

No NBA team has overcome a 3-0 deficit to win a series but Boston is now halfway there after staving off elimination for the third and fourth times this postseason. The Celtics also recorded two such wins against the Philadelphia 76ers in the conference semifinals.

"Our back has been against the wall," Boston standout Jaylen Brown said after Thursday's 110-97 home win. "Obviously, we didn't imagine being in this position, being down 3-0, but when adversity hits, you get to see like what a team is really made of. I mean, it couldn't get no worse than being down 3-0, but we didn't look around, we didn't go in separate directions. We stayed together. We doubled down on what we're good at on defense, and now I think it's a series."

The Celtics never trailed and led by as many as 24 points in Thursday's game. Two nights earlier, they led by as many as 18 during a 116-99 road win.

The stellar play comes after Boston appeared ready to start the offseason after it was whipped 128-102 in Game 3.

"Game 3, that was as low as you can be," Celtics star Jayson Tatum said. "The good part about being that low is you only can play better. It's only up from there.

"It kind of gave us a sense of just like everybody is counting us out. We're supposed to win. We're supposed to be done, and I think we started to play a little bit more free and relaxed."

Suddenly, the pressure is on the Heat.

The thought of possibly playing a Game 7 in Boston in a winner-take-all affair isn't appealing.

And that makes Saturday's contest feel like a must-win for both teams.

Yet Miami star Jimmy Butler is downplaying his team's recent issues.

"We've just got to play better," Butler said. "... We are always going to stay positive, knowing that we can and we will win this series. We'll just have to close it out at home."

Butler scored a series-low 14 points and has failed to reach 20 in two of the past three games.

Heat coach Erik Spoelstra befuddled Joe Mazzulla over the first three games but it was the first-year Celtics coach pushing all the right buttons over the past two games.

"One game doesn't lead to the next game," Spoelstra said. "It just doesn't matter. It's about collectively preparing and putting together a great game. We'll play much better on Saturday. That's all we just have to focus on right now."

Mazzulla didn't have any profound explanation for the turnaround.

"It just says that our backs are against the wall and we're sticking together and we're competing at a high level to give ourselves a chance," Mazzulla said.

Heat center Bam Adebayo made it clear that his club's confidence remains high.

"When we started this journey, nobody believed in us," Adebayo said. "Everybody thought we were going to be out in the first round. Everybody thought we were going to be out in the second round. And now we are here one game away."

Boston had four 20-point scorers in Game 5. Derrick White made six 3-pointers and led the way with 24 points, Marcus Smart scored 23 and Tatum and Brown each scored 21.

Duncan Robinson led Miami with 18 points.

Heat guard Gabe Vincent (ankle) missed Game 5 and his status for Saturday hasn't yet been firmed up.