After the Boston Celtics stomped out his Cleveland Cavaliers to open the 2018 Eastern Conference finals on Sunday, LeBron James kept it cool, insisting he had “zero level of concern at this stage” with his team down a game in the best-of-seven set. He might not deign to admit it, but facing an 0-2 deficit after the Cavs got thoroughly outplayed down the stretch of a game in which he’d put up the third 40-point triple-double of his career? That probably ought to concern him just a smidge.

Coming off a disappointing start to the series, Brad Stevens’ Celtics expected to get a monster effort from James in Game 2. He obliged, scoring a game-high 42 points on 16-for-29 shooting with 12 assists, 10 rebounds and a block in 42 minutes of play …

… and it barely made a lick of difference.

Boston choked out the Cavs in the second half, limiting the three-time-defending Eastern Conference champs to 39 points on 39 shots after halftime before pulling away in the closing minutes for a 107-94 win. The Celtics have successfully defended home court, drawing within two wins of the NBA Finals and giving LeBron, coach Tyronn Lue and the rest of a disheveled-looking Cavs team an awful lot to think about in the extended three-day layoff before the series resumes in Cleveland with Game 3 on Saturday.

The last Eastern team to put LeBron in an 0-2 hole? They wore green, too. And they won it all.

Jaylen Brown continued his strong postseason, routinely attacking off the bounce when guarded by James and in the post when guarded by the likes of Kyle Korver on his way to a team-high 23 points on 9-for-18 shooting, seven rebounds, three assists and a steal in 35 minutes. He led six Celtics in double figures, all of whom made their presence felt at opportune times.

Jayson Tatum (11 points, three rebounds, two assists) and Marcus Morris (12 points, five rebounds, three assists) each hit big shots in the second quarter to help keep Boston within striking distance when the Cavs made an early push. Point guard Terry Rozier poured in 14 of his 18 points in a third quarter that saw Boston blow the game open, outscoring Cleveland 32-16 over the final 9:15 of the frame to seize control.

After a slow start, Al Horford took the game over late, finishing with 15 points, 10 rebounds, four assists, two steals and two blocks in 38 minutes; he scored or assisted on 10 of Boston’s last 12 points. And with or without a working jumper, Marcus Smart continued to disrupt Cavs possessions and earn Boston new ones on his way to 11 points, nine assists, five rebounds and four steals in 31 minutes of turnover-free basketball during which the Celtics outscored visiting Cleveland by a whopping 21 points — the highest plus-minus mark of the game, and one befitting the massive impact he makes with his defensive talent and unbridled tenacity.

Kevin Love did his level best to offer James support, scoring 22 points on 9-for-18 shooting with 15 rebounds and a pair of assists in 35 minutes. Ditto for Korver, who scored 11 points in the second quarter to help the Cavs withstand a brief breather for James early in a period during which the Cavs would briefly lead by as many as 11. But once again, Cleveland’s complementary pieces got outproduced and flat-out outworked by their Boston counterparts.

Rodney Hood gave Cleveland next to nothing in his 11 minutes off the bench. Jeff Green was worse than that, leveling his six points with five turnovers and shoddy defense on his way to a -17 in 28 minutes that felt exactly the way it looks in print. J.R. Smith had them both beat, missing all seven of his shots from the field, and routinely getting his lackadaisical defense roasted by Brown and Rozier.

Smith put a bow on it all late in the fourth, delivering a dirty two-hand shove to the back of an airborne Horford as he elevated for a lob in the lane, sending the All-Star center to the deck in a heap and earning himself a flagrant foul-1 that, frankly, probably should’ve been a mandatory-ejection-triggering flagrant-2:

It was a fitting end to an awful night for the rest of the Cavaliers, a piecemeal roster featuring holdovers from a title team and midstream additions who’ve yet to really make their mark on this postseason push. With them offering precious little, and Cleveland’s season-long aversion to defense continuing to rear its ugly head against a Celtics team that sticks and moves, the Cavs now find themselves behind the 8-ball in a way they haven’t in years.

As he’d hinted he would after a poor defensive outing in Game 1, Cavs coach Tyronn Lue elected to shake up his starting lineup. He sent Korver to the bench, calling on center Tristan Thompson to resume his years of unpleasantries with Horford while kicking Love down to power forward.

The Celtics didn’t super-size to meet them, though, holding firm in the belief that their lineup — Horford and Morris up front, Tatum and Brown on the wings, Rozier at the point — would continue to generate quality looks against a more conventional Cavs defense, and would still be able to match up against the beefier Thompson-Love-James frontline. (Thompson was fine, scoring eight points, grabbing seven rebounds and playing physical defense, but he wasn’t The Answer for what ails these Cavs.)

Also as expected: LeBron opened the game like freaking Godzilla.

After a couple of early turnovers trying to attack, James began to grab the game by the scruff of its neck, much as he did in Game 2 of the opening round against the Indiana Pacers after Cleveland dropped the first game of that series. He fired away from deep, spun into the lane for layups, and bailed out well-defended possessions with the sort of fadeaway bomb that buried the Raptors on his way to 21 points, tying the highest-scoring quarter of his postseason career, on 8-for-13 shooting with four 3-pointers.

(Here’s where we remind you that he scored 15 points on 16 shots in all of Game 1, and that Cleveland as a team made only four 3s in the first game of the series.)

Despite LeBron’s remarkable start, though, the Celtics hung tight. They trailed by just four after 12 minutes, 27-23, thanks in part to a stellar start by Brown (14 first-quarter points on seven shots) and in part to some still-spotty defense by a Cavaliers team more likely to overreact to a hard cut than to stay at home on a red-hot shooter: