CLEVELAND -- A veteran of more than 200 NBA playoff games, Cleveland Cavaliers small forward LeBron James knows very well when it is time to step up his level of production, and the fourth quarter of Game 4 against the Boston Celtics in the Eastern Conference Finals at Quicken Loans Arena Tuesday night was one of those moments.

After scoring 19 points over the first three quarters, James knocked down seven shots and tallied 15 markers over the final 12 minutes, which, when coupled with a single-game playoff high of 42 from point guard Kyrie Irving, led to a 112-99 victory over the Celtics and 3-1 lead in the best-of-seven series.

“Just trying to be aggressive,” James said. “Obviously, I couldn't be as aggressive as in the first half because of the foul trouble, so if I'm on the floor, I've got to be aggressive and try to make plays, help our team be successful and read the defense.

“I was able to still be aggressive and find two of our shooters for two threes, found Kev, found Swish [J.R. Smith], so it was just trying to read the game, the game in-between the game, and it worked well for us.”

After a season-low 11 points in Sunday’s Game 3 loss and despite making just one of his six three-point attempts, James scored 34 points on 15-of-27 shooting. Additionally, James pulled down five rebounds, handed out six assists, blocked one shot and stole a pass.

But when James went out of the lineup because of foul trouble, his teammates provided a lift, one that he kicked over the top in the fourth quarter.

“We needed his pop and his spunk, and I didn't think he would get a fourth foul called on him, but he did,” Cavaliers coach Tyronn Lue said. “He went to the bench, and then, Kyrie kept us afloat, Kevin kept us afloat, and we got it down I think to eight and Horford banked in a three from the top of the key and we got a good run going.

“I told the guys at halftime, ‘Until we get into the fight, it's going to be like this all night.’ I thought they really came out, they took it to us. They were more physical, they were more aggressive, and until we decided to play and get physical back and start guarding and defending, it was going to be a long night.”

In that fourth quarter, James converted seven of his 11 attempts from the field and one of his two three-point tries, and that triple made it a three-possession game after the Celtics had trimmed the Cavaliers’ advantage to just six points with back-to-back 23-foot jumpers from Avery Bradley and Jonas Jerebko.

“My rhythm, for the most part, is broken when you -- I can't remember the last -- I don't think I've ever had four fouls in a game before in the first half, so my rhythm is kind of broken and you've got to figure out ways you can still help the team,” James said.

“My teammates said, ‘Be aggressive. Be you. You got us to this point and continue to do that,’ so I just tried to find ways to get into the lane, get into transition, when they backed off shoot the jumper and felt very comfortable with it, so I was able to get back into a rhythm very fast.”