SAN ANTONIO — Even after winning 27 in a row during the regular season, the Miami Heat don’t want to rely on a three-game winning streak now.

Not against a team as good as the San Antonio Spurs.

The Spurs can take a 3-1 lead in the NBA Finals on Thursday, which would move the Heat to the verge of something much bigger than just another finals failure.

Lose this series, and the whole Big Three era might be a failure.

So LeBron James called Game 4 a “must-win,” and pointed to himself as the guy who has to lead the Heat to it.

“We’ve been at our best when I guess our backs are up against the wall, and we’re at it again,” he said Wednesday. “We’ll see how we respond tomorrow.”

Any questions about James and the Heat were supposed to have been answered by now. He was too good to be taken out of games, his teammates too talented to go through long stretches where they weren’t contributing.

But they didn’t resemble the league’s reigning powerhouse in Game 3, when the Spurs handed them the third-worst beating in finals history in a 113-77 romp. They looked like the confused club from two years ago against Dallas, when the finals last came to Texas.

“Something has to give tomorrow night,” James said Wednesday. “They have a championship pedigree. They have four (titles). We have two. So something has to give. We’ll see what happens. We’ve been able to bounce back throughout adverse times throughout the season, throughout the years that we’ve been together, these three years. We’ll see.”