Then a 20-year-old rookie lit them up.
Heat guard Tyler Herro lived up to his last name in Game 4, scoring a game-high 37 points on 14-of-21 shooting off the bench to lead Miami to a 112-109 win that put the Celtics in a 3-1 series hole.
Some would argue Herro's outburst came out of nowhere, but on a new Celtics Talk Podcast with NBC Sports Boston's A. Sherrod Blakely and Chris Forsberg, host Kyle Draper suggested Boston should have done more to stop the talented rookie.
"The fact that you had a guy who had 22 (points) in Game 3 and you let him go off for 37? That can't happen," Draper said. "As good as Tyler Herro is, you cannot let a bench guy come in and gas you for 37 and just dominate."
Herro scored 22 of his 37 points in the second half, hitting four 3-pointers and slicing through the Celtics' defense for eight more buckets within the arc.
For Blakely, Herro's ability to score at will late in the game is an indictment on Celtics head coach Brad Stevens.
"I was just shocked that they didn't make any type of legitimate, serious adjustments to the way he was shooting," Blakely said. "At no point did they blitz him. At no point did they double him. They didn't do any of the gimmicky things that you do not so much to shut him down, but just to throw him off his rhythm a little bit.
"That was disappointing. And when you break it down, that's coaching."
Blakely pointed to a sequence when Boston blitzed Heat star Jimmy Butler and forced him to pass to Bam Adebayo at the free throw line. While Adebayo made the shot, it was one the Celtics could live with rather than continually getting beat by Miami's hot hand.
"The way Tyler had it going, you had to get that ball out of his hands whenever he touched it to see if Iguodala or Butler could knock down a shot," Blakely said.
" ... There were so many different things from an Xs and Os standpoint that I think the Celtics could have tweaked a little bit to give themselves a better shot, and it just didn't happen."
Can the C's make the necessary adjustments to win Game 5 on Friday night and keep the series alive? The crew discussed Boston's chances of mounting a comeback and more on Thursday's episode of the Celtics Talk Podcast.