MIAMI — Here they are again, back on the brink of a championship.

It slipped away from the San Antonio Spurs last year, but it would take something special — historic, actually — to stop them now.

The Miami Heat would have to make the biggest comeback in NBA Finals history.

“They’re the two-time champs, they’re a great team, and there is still one more game,” Spurs guard Tony Parker said. “We have to win one more game.”

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Kawhi Leonard had 20 points and 14 rebounds, and the Spurs routed the Heat again, winning 107-86 on Thursday night to open a commanding 3-1 lead.

The Spurs can win their fifth NBA championship with a victory at home in Game 5 on Sunday and avenge their seven-game loss to Miami last year. They have three chances, and the way they’re dominating the Heat, they might need just one.

“I’m pleased that they performed as well as they did while we’ve been in Miami, and that’s about as far as it goes,” Spurs coach Gregg Popovich said. “Now we’ve got to go back home and play as well or better.”

LeBron James had 28 points and eight rebounds, but Dwyane Wade was just 1 of 10 through three quarters and finished with 10 points.

“They smashed us,” James said. “Two straight home games got off to awful starts. They came in and were much better than us in these last two games. It’s just that simple.”

No team has overcome a 3-1 deficit in the Finals, and the way the Heat was outclassed twice on its home floor makes it hard to imagine the two-time champions being the first.

“We put ourselves in a position where it is about making history,” James added.

Parker added 19 points, and Tim Duncan had 10 points and 11 rebounds for the Spurs, who shot 57 percent from the field and are hitting 54 percent in the series.

The Spurs lost twice in Miami to end last year’s Finals, their only defeat in the championship round. They won their two games in South Florida this time by a combined 40 points.

San Antonio’s surprising dominance has Miami on its heels, and unless Miami can figure things out quickly, the Heat’s two-year championship reign will come to an abrupt end.

If this was the last home game of the season in Miami, it looked and sounded nothing like the ones to end the past two years, which featured confetti falling and trophies raised. This one had the unfamiliar sound of boos late in the first half and a chant of “Go Spurs Go!” with under three minutes left from the San Antonio fans who remained long after many of Miami’s had bolted.

A Heat win Sunday would force a Game 6 in Miami on Tuesday.

The Heat had followed its last 13 postseason losses with a victory. But now at the end of a fourth straight season that has gone the distance, the Heat might be out of gas. Miami seemed to lack the energy — or maybe effort — to defend San Antonio’s precision ball movement for the full 24 seconds, and time after time the Spurs ended up with a shot from somebody who didn’t have a defender nearby.

“They played great and I can honestly say I don’t think any of us were expecting this type of performance,” Heat coach Erik Spoelstra said.

LOS ANGELES — Clippers owner Donald Sterling’s team of lawyers has hired four private investigation firms to dig up dirt on the NBA’s former and current commissioners and its 29 other owners, said a person familiar with Sterling’s legal strategy.

Investigators were given a six-figure budget over the next 30 days to examine the league’s finances, allegations of previous discriminatory conduct and compensation to past commissioner David Stern and current commissioner Adam Silver. The person said the investigators also are looking into whether other owners made any off-color jokes, or racist or sexist remarks.