Dallas ? LeBron James was looking for the best win of his playoff career.

Instead, almost stunningly, he turned in his worst postseason scoring performance.

For the first time in 90 postseason games — and his last 434 overall — James did not reach double digits in the scoring column. His offense was, by his lofty standards, offensive: a mere eight points on 3-for-11 shooting, and the Miami Heat lost, 86-83, to the Dallas Mavericks on Tuesday night.

The series is even at two games apiece, with Game 5 in Dallas on Thursday.

And here’s a certainty: Between now and then, every aspect of James’ offensive shortcomings in Game 4 will be scrutinized in about every way possible.

“Obviously, we’d like to get him involved,” Heat coach Erik Spoelstra said. “He’s a very important piece to what we do. So we’ll work to help make it easier for him in the next game.”

Although James finished with nine rebounds and seven assists, his night will be considered a clunker — a big one. Spoelstra said the two-time MVP is physically fine, and took the blame for what he said was not putting James in the best opportunities offensively.

“I’ve got to do a better job,” Spoelstra said.

The last time James scored under 10 points was Jan. 5, 2007.

That night in Milwaukee — also an eight-point effort — has long been forgotten.

This one, on the NBA’s biggest stage, certainly will not be forgotten anytime soon. And he was scoreless in the fourth quarter, meaning he’s got a total of nine points in the final periods in these four games with Dallas.

“Let’s continue to play desperate,” James told his teammates before the game. “That’s the only way we know how to play basketball. That’s the best way we know how to play. When we play desperate, we feel like our back is against the wall.”

It’s a safe bet he will feel even more desperate on Thursday night. He was a lightning rod for criticism after Game 3, when he was asked if he’s shrinking away from the moment.

James brushed that question off. He’ll hear it again, a lot, until Thursday night.

James tried one shot in the fourth quarter, and was 2-for-7 after halftime — one of those an open dunk in transition, the other a jumper late in the third quarter when Miami had a chance to pull away.

It wasn’t just James, struggling, either. Miami had nine points in the final 10 minutes, wasting a lead again for the second time in the series. Udonis Haslem’s jumper gave Miami a 74-65 lead, but it quickly disappeared from there for the Eastern Conference champions.

“Our team defense really stepped up in the fourth, which we had to do because we were playing from behind,” Mavericks coach Rick Carlisle said.

It’s the ninth time in his career James was held to single figures, though most of those came when he was a rookie. Of his 90 playoff games, he had scored at least 20 in 78 of them. And for his career, it was just the ninth time in 717 games where he didn’t reach double digits.

“We’ll be better in Game 5,” Spoelstra said.