Subs spark B’klyn’s 40-point, 2nd-quarter blitz

It started innocently enough, with Landry Shamet knocking down the go-ahead jumper off the dribble in the paint.

Who would’ve thought that one seemingly unremarkable play Sunday by the Nets’ second unit marked the beginning of the end for the Celtics in Game 4 — and maybe in this playoff series?

Because then James Harden pulled up for 3. Then Joe Harris set up two straight baskets, a one-hand slam by a cutting Harden and a pull-up jumper by Tyler Johnson. Then the onslaught kept coming with Harris connecting for a 3 and Harden blowing past the overmatched Evan Fournier and Tristan Thompson for back-to-back driving layups against a slow-rotating help defense.

“When the ball moves like that and we have multiple shooters on the floor, we can put teams under a lot of pressure,” coach Steve Nash said. “They had a nice little run there and that was the start of us getting control of the game.”

In what felt like the blink of an eye, a one-point deficit became a nine-point lead in the first five minutes of the second quarter as the Nets looked scarily efficient, converting 7 of 7 shots in that span. The scariest part? You haven’t yet read the names Kyrie Irving and Kevin Durant because they were on the bench for the entire blitz.

The second quarter of this 141-126 rout by the Nets at TD Garden was as close to a perfect 12 minutes as you’ll see in the NBA playoffs. If there were 17,226 fans in the expanded capacity crowd, they were eerily quiet as the Nets went up by 16 en route to a 73-60 halftime lead.

“Not just [trying] to score but be a playmaker,” Harden said. “I just saw spots where I could be aggressive.”

In all, the Nets shot a ridiculous 17 of 24 from the floor, including 5-for-8 from 3, on the way to a 40-point outburst. Ten of the baskets were assisted, breaking away from the dangerous one-on-one isolations. Durant, after scoring 17 in the first quarter to offset Jayson Tatum’s 14-point start for the Celtics, contributed exactly two of his game-high 42 points — the same as Johnson, Shamet and Bruce Brown.

Harden, meanwhile, had 15 points and six assists in the second quarter, meaning he factored into 13 of the 17 baskets after playing third fiddle in the first. Irving and Durant combined for 29 of the Nets’ first 33 points but the Celtics led 34-33 after one.