BOSTON — Charles Barkley walked into TD Garden for Friday night’s television gig and greeted a familiar face with the words, “Came in for this mercy killing.”

Sir Charles clearly had no idea how right he would be.

The champion Cavaliers exploded to a 72-31 halftime lead — the largest halftime advantage in playoff history — and cruised to 130-86 blowout of the Boston Celtics to take a 2-0 lead in the Eastern Conference finals.

It was the biggest playoff win ever for the Cavaliers, while the Celtics fell three points shy of matching their worst postseason defeat.

LeBron James, who scored 22 of his 30 points in the first half, has never lost a playoff series when up 2-0 and this series now shifts to Cleveland for Games 3 and 4 Sunday and Tuesday with outmanned Boston just trying to bring it back home for Game 5 Thursday night.

The win was the 13th straight playoff victory for the Cavs, who have not lost since Game 4 of last year’s NBA Finals. The streak tied an NBA record.

James, the first player since Kareem Abdul-Jabbar (1970) with eight straight 30-point playoff games, and the rest of the Cleveland starters were pulled with 1:47 left in the third quarter.

To make things worse for the Celtics, Isaiah Thomas was lost to a right hip strain at halftime. He was scoreless, missing all six shots in the first half, but he did assist on six of his team’s 11 baskets in the half.

James, who was a plus-46 in the game (plus-63 in two games), dished out seven assists and added four rebounds, four steals and three blocked shots, while Kevin Love had 21 points and 12 rebounds and Kyrie Irving 23 points. The trio went a combined 11 of 21 from 3-point range.

The Cavs, who went 19 of 39 from 3-point range (Boston was 8 of 27), have never trailed in the first two games.

Rookie Jaylen Brown led the Celtics with 19 points and Avery Bradley had 13.

NOTES: The Celtics made one lineup change, starting G/F Gerald Green in place of F Amir Johnson. “He’s always been ready, and he always stays ready,” Boston coach Brad Stevens said of Green, who logged 13:44 and scored 11 points off the bench in Game 1. Cavs coach Tyronn Lue called it a “smart? Move” and he hit a pair of first-quarter 3-pointers. … The Cavaliers shrugged off two aggressive plays by Boston G Isaiah Thomas in the opener, the second a hard foul on a driving LeBron James that actually knocked the smaller Thomas’ headband from his head. “It wasn’t as bad as I thought it was,” said Lue, who was asking for a review for a potential flagrant. … The Cavaliers won their two home games against Boston in the regular season by six points apiece but the Celtics haven’t played in Cleveland since Dec. 29. … Rob Gronkowski and owner Robert Kraft were among the Patriots seated courtside