CLEVELAND -- The NBA Playoffs are proving ground for players, times to see whether their talents match up with the ability to handle the pressure of increased physicality, a higher level of intensity and meaningful moments at every point of the game.

From hitting the championship-winning shot against the Golden State Warriors in the 2016 NBA Finals to stepping up at a time when small forward LeBron James was struggling through foul trouble, Cleveland Cavaliers point guard Kyrie Irving has never shined away from that kind of stage.

In Tuesday’s 112-99 win over the Boston Celtics in Game 4 of the Eastern Conference Finals, Irving led a comeback from 16 points down and set a new single-game playoff best along the way with 42 points, a performance that gave the Cavaliers a 3-1 lead in the best-of-seven series.

“Just being prepared mentally first, and then, letting the physical tools that God has blessed me with take over and really being just fearless in terms of my approach,” Irving said.

On the strength of 14 straight points from Irving, the Cavaliers came all the way back from a double-digit deficit early in the second half and took an 87-80 lead over the Celtics after the third quarter.

Down by 12 in the early part of the third quarter after a Celtics basket, the Cavaliers slowed chipped away at the deficit with Irving and James at the forefront of the comeback effort.

After Irving made a driving layup, James buried a 17-foot jump shot. Then, James caught a pass from Irving and threw down a slam dunk that brought the crowd to its feet and got the Cavaliers to within seven points of the Celtics, 61-54, with 8:42 to play in the third quarter.

Irving made two straight driving layups in the lane to put the Cavaliers up by five points, 77-72, but on the second shot, he fell to the floor and reached for his lower left leg, which caused concern throughout the arena.

However, after retying his left shoe, Irving jogged down to the defensive end, and hit a driving jump shot on the next possession. Then, Irving completed a three-point play with 1:02 left in the third quarter and beat the buzzer with a deep three-pointer at the end of the period.

“I don't take it for granted to have great teammates because without those guys, I'm not able to attack the rim and be able to create, and be able to have the space that I have out there,” Irving said. “Boston did a great job loading up on our isos, but we sort of took advantage of it in the second half.”

On his way to the 42 points, Irving converted 15 of his 22 attempts from the field, including four of his seven looks from three-point range and eight of his nine free throws. Along with the points, Irving pulled down three rebounds and assisted on four baskets.

“You just have to be really confident in who you are as a person and stay true, and then, make decisions from there and be able to play basketball at a very high level, and you can't cheat the game,” Irving said.

“I've learned from some of the best that have played this game, and you can't cheat it. I've become more of an observer as well as a leader at the same time, which I'm super proud of. So it all comes with the great veteran leadership we have on this team that allows me to do that.”