Win three at home and it’s over.

The NBA Finals resume Sunday night at AmericanAirlines Arena with Game 3 of the best-of-7 series. After surviving Game 2 of the Finals in Oklahoma City and handing the Thunder its first loss at home in the playoffs, the Heat has no desire to travel back to the middle of America — and Oklahoma City’s thunder dome — to finish the job.

“They understand the importance of playing well at home,” Heat coach Erik Spoelstra said of his team.

But do the Heat’s fans understand the importance of home-court advantage?

With three consecutive games now on Biscayne Boulevard, the Heat has a chance to close out the series in front of its fans — fans that have gotten a bad rap in the NBA. Around the league and on national TV, Miami’s fans have been chided for two seasons for not arriving on time to games and for sitting on their hands when they finally show up.

In Oklahoma City, the battle cry is “Thunder Up.” In Miami, the Heat has pleaded with its patrons to simply “Fan Up.”

For the past month, LeBron James, who left his hometown to come to Miami, has been playing basketball like he has something to prove. The Heat’s fans now have something to prove as well. Did they deserve him?

“My days in Cleveland, we were very dominant at home in the postseason and in the regular season,” James said Saturday, a practice day for the Heat and Thunder. “You want to try to establish that. When people come into the building, they feel like they’re at a disadvantage already before the game starts.

“And our fans here are great — have been great throughout the whole postseason in the last two years. And in Game 7 of the Boston series that just ended, it was the loudest they’ve been. They were very excited about us winning that game and moving on to the Finals.”

Does it take a Game 7 scenario to bring out the best in Miami’s fans? If so, the Heat might be in trouble. Games 6 and 7 of the series would be in Oklahoma City.

“At one point I was shooting a free throw, and it was the loudest I’ve ever heard it,” said Dwyane Wade of the atmosphere in Game 2 at Oklahoma City’s Chesapeake Energy Arena.

Can Miami match the raucous atmosphere Oklahoma City provided the Thunder?

This might come as a shock to the city of Miami, but the Heat isn’t supposed to win this series. The Thunder is favored. The Thunder is the deeper team. The Thunder defeated the Mavericks, the Lakers and the Spurs to get this far.

James, Wade and Chris Bosh are going to need all the help they can get this week.

“A lot of stuff has been said about our fans, and it will always be said about our fans, but they’re our fans,” Wade said. “We love them. We appreciate them.”

Time to return the gesture, Magic City.

Ever since James and Bosh joined Wade in 2010, there has been an air of entitlement around Miami about the team, as if it’s supposed to walk through the season and playoffs with ease. During home games, that expectation has manifested itself in a fan base that mostly observes games and cheers when there’s a dunk.

In opposing arenas during the playoffs — New York, Indiana, Boston and Oklahoma City — the energy provided by fans was almost an active participant in games. For two seasons now, when the Heat has visited a city, fans have acted as if it was there job to defeat the Heat with boos, personal attacks, foul language and enough noise to register on seismographs.

In Miami, when the Heat has trailed in games in the playoffs, its fans have watched meekly in stunned silence.

To a degree, the relatively reserved atmosphere at AmericanAirlines Arena, compared with rival towns, is almost understandable. James predicted multiple championships during the Heat’s preseason pep rally in 2010 and, since then, that level of dominance has been expected.

But now, for the first time in a playoff series in the Big 3 Era, the Heat is the legitimate underdog. According to oddsmakers in Las Vegas, the Heat isn’t supposed to win.

Maybe Vegas picked the Thunder because Kevin Durant, Russell Westbrook and James Harden are better on paper. Maybe Oklahoma City was the favorite to begin the series because it had home-court advantage.

Not anymore.

“We love our fans, too, and I think they’re excited about this game [Sunday],” Wade said. “I think they’re going to be as loud as they can possibly be.”