The end came as expected, the Miami Heat on the second night of a back-to-back set running out of gas in Sunday night’s 124-112 loss to the Oklahoma City Thunder at Paycom Center.

Against the team with the best record in the league, it’s not as if even the best of Heat nights might have been enough against the rested defending NBA champions.

But it was the cumulative of the weeklong trip that has the Heat teetering, the record down to 20-19, after yet another inability to sustain.

In the end, a week that wasn’t.

First, the 122-94 loss to the Minnesota Timberwolves, when coach Erik Spoelstra lamented the lack of fight.

Then nearly a two-hour delay and eventual postponement of the game against the Chicago Bulls, due to condensation at the United Center.

From there, the abject humiliation of Saturday night’s 123-99 loss to the league-worst Indiana Pacers at Gainbridge Fieldhouse, when Spoelstra questioned his team’s readiness.

And then fighting a good fight against the Thunder before being undone by an 18-2 Oklahoma City run in the third period.

“It feels like we’ve been on the road for a month,” guard Davion Mitchell said.

Spoelstra stopped short of calling this one capitulation.

“You just have to be overall tougher with everything,” he said. “But it’s not just physical toughness. I felt like we brought a physical toughness, but the mental toughness when the game starts to go or the momentum starts to swing the other way.”

With Norman Powell sidelined by a back issue and Bam Adebayo again unable to find consistency with his offense, the counters were limited to the 29 points the Thunder got from defending NBA Most Valuable Player Shai Gilgeous-Alexander.

For the Heat, there were 23 points from Andrew Wiggins, 19 from Tyler Herro in his second start since being sidelined Dec. 9 by a toe contusion and 16 from Pelle Larsson.

Adebayo closed 3 of 10 for six points, albeit with 14 rebounds.

“We’ve got to run more, take care of the ball more and get stops,” Larsson said.

Five Degrees of Heat from Sunday night’s game:

1. Game flow: The Heat went up nine early and took a 34-32 lead into the second period. From there, the Heat moved to a 59-54 lead at the intermission.

A 15-0 Thunder run midway through the third quarter then turned the tide, with Gilgeous-Alexander basically unstoppable in the period, scoring 16 in the quarter.

That allowed the Thunder to take a 93-85 lead into the fourth.

From there, the Thunder pushed their lead to 20, as the Heat’s season-high 23 turnovers simply took too much of a toll, leading to 39 Thunder points.

“The turnovers offensively for us allowed them to get back into it and take control,” Spoelstra said.

Still, close enough for long enough for hope going forward.

“We will get better,” Spoelstra said. “Hopefully, it will be in a lot more of these kind of close games where we can feel that emotion collectively and respond in a better way.”

2. Another twist: Continuity continues as an abstract for the Heat, this time with Powell this time sidelined with lower-back soreness.

The absence came a night after Powell was limited to six points in the loss in Indiana, his first time scoring in single digits with the Heat.

With Powell out, Larsson got his eighth start of the season, as Powell missed his sixth game.

Larsson closed 6 of 11 from the field.

“I think we took a step in the right direction,” Larsson said of at least competing for an extended stretch, “played a little bit better.”

Larsson said he was ready when called.

“It’s really no different,” he said of starting. “You get a little hype you’re going to start, and then take that into the game.”

3. Rotation reversal: After being held out of the first three periods Saturday, not entering until 11:43 remained, Dru Smith this time entered with 4:04 to play in the opening period.

With Larsson, Herro, Adebayo, Wiggins and Mitchell starting, the second unit was composed of Smith, Jaime Jaquez Jr., Nikola Jovic and Kel’el Ware.

Jovic had his moments with his shooting, at 3 of 4 on 3-pointers, but Ware continues to be mostly afterthought when cast as a reserve, playing just 16 minutes and finishing with eight points and just one rebound.

It was the second consecutive game off the bench for Ware after starting the previous 11.

4. Efficiency upgrade: A night after shooting 4 of 30 on 3-pointers, the Heat this time made their first four attempts from beyond the arc, a pair of conversions from Wiggins, one from Larsson and one from Mitchell.

The Heat’s first missed 3-pointer attempt was a 27-foot attempt by Adebayo with 7:59 to play in that opening period.

The Heat closed 17 of 32 from beyond the arc, with Wiggins 7 of 10 and Mitchell 3 of 3.

“That was kind of our game plan, get as many threes as we can, honestly,” Mitchell said, “just because we know they’re gonna swarm the paint.”

5. Still struggling: The offensive woes continued for Adebayo, who did not score his first points until converting a 10-foot jumper after an 0-for-3 start.

Adebayo entered with three single-digit scoring efforts in his previous seven games, including nine points in Saturday night’s loss to the Pacers.

The time he closed 3 of 10 from the field.

Wiggins said, as a team, the Heat can’t give in to the moment.

“It’s a long season,” he said. “Things can change. So we’ve got to stay with it and stay together — don’t get down on ourselves and keep fighting.”