Portland Trail Blazers' Jusuf Nurkic, bottom foreground, and Boston Celtics' Daniel Theis lie on the court after colliding during an NBA basketball game Sunday, Aug. 2, 2020, in Lake Buena Vista, Fla. (Mike Ehrmann/Pool Photo via AP)

As usual in these early games Kemba Walker sat out crunch time, though based on his first-half work Sunday and even Friday night, the Celtics point guard is going to be an explosive addition once allowed to play a full minutes load.

But Sunday’s tremulous 128-124 win over Portland was about something Walker has a great appreciation for — the two young stars who are supposed to take away so much of the burden.

And they did exactly that. Jayson Tatum shrugged off Friday night’s misfires against the Bucks to score 21 of his 34 points in the first half against the Blazers, when the Celtics were running out to a peak 24-point lead.

And when the Celtics lagged in the third, allowing Portland’s molten backcourt to reach peak heat and take several leads down the stretch, led by Damian Lillard’s 30-point night after a 1-for-6 start, the other end of the equation checked in.

Jaylen Brown scored 16 of his 30 points in the fourth quarter, and in the most dramatic form imaginable — with four 3-pointers, a tie-breaking turnaround jumper, a tomahawk dunk, and four rebounds.

“They were special,” Walker said of the young pair. “In order for us to be a great team, those two guys are going to have to go at it every night, they’re going to have to balance off each other. They’re gonna have to love each other, because their talent level is unreal, and it could take our team to great heights when they’re playing basketball on that kind of level.”

Sunday, unfortunately, every drop of what Brown and Tatum produced was needed once the Celtics not only squandered a 24-point lead — remember those times? — but continued to show weakness against a tough opposing big man. In this case the damage was done by Jusuf Nurkic, who had it his way in the paint with 30 points and nine rebounds.

But the Celtics are also now 1-1 after a pair of tight results in their restart. There’s a lot to build from.

They’re getting some early tempering: Their loss to the Bucks was eminently winnable, and with even a smidgeon more of production from Tatum, the Celtics could be 2-0. Then again, based on how powerfully Lillard, Nurkic and Gary Trent Jr. blew through the second half door, they could just as easily be 0-2.

If this is to be the nature of their games in the Orlando bubble — they play Miami Tuesday — then the Celtics stand to benefit once the playoffs begin in mid-August.

“These are really valuable. The one thing we talked about is you’re going to play all good teams,” said Brad Stevens. “All teams that are either ranked high in their conferences or fighting for their lives to make the playoffs. That was a playoff level energy we had to play with at the end of the game and we played with most of the game because Portland’s in the position they’re in and they’re good. I think this is great experience. Obviously, it remains very difficult on Tuesday with a Miami team that I thought played great (Saturday night).”

About that Heat team; they’re only two games behind the Celtics: The Heat, with Kelly Olynyk (!) scoring all 20 of his points in the fourth quarter, dominated Denver on Saturday, and had pulled as close as a game-and-a-half to the Celtics.

That talk about the possibility of the C’s eventually falling back to the fourth seed is very real. That talk about the Celtics catching Toronto for the second seed is brave, especially after watching the Raptors tough out a win over the Lakers on Saturday night. Toronto now leads the Celtics by three-and-a-half games.

All of these teams have tough interior players. That continues to be a Celtics weakness: Daniel Theis simply isn’t built to handle an isolated Nurkic in the post, just as he wasn’t the best option to get in the way of Steven Adams when the OKC center tore the Celtics apart in a recent scrimmage.

Enes Kanter may have to be deployed differently. It will be a project over the next six seeding games.

“Well, you pick your poison against these guys,” said Stevens. “How much do you really want to give off Lillard and (C.J.) McCollum when they’re standing at the 3-point line, how much do you want to be back on their pick-and-roll because they’ll just pull up and shoot threes, so you pick your poison a little bit.

“Today was not like when Adams hurt us from a standpoint of, that was just open layups and dunks. These were at least like a body, we got back in front, we at least made a contest. We did the best we could. We don’t have unbelievable size in there, and if we (change) it would take away maybe some other things we do really well so you just pick your poison and be as good as you can be.”

One key for Tatum beating the blitz? Better passing: In addition to going for 34 Sunday, Tatum posted a career-high eight assists. He’s finding ways to make opponents pay for loading up on defense. Brown’s last 3-pointer, a game-sealing dagger with 32.3 seconds left, was set up by Tatum. Indeed, Tatum assisted on all four of Brown’s 3-pointers in the fourth.

“It’s just making reads. It’s as simple as making the right pass,” said Tatum. “You see a double team, you’re drawing a lot of attention, somebody’s going to be open. It’s as simple as making the right play. I drove and kicked it to JB (Jaylen Brown) — he was open. It was just the right, easy play to make.”