Published: Mar 24, 2012 6:06 PM EDT
Updated: Mar 25, 2012 6:32 AM EDT

OKLAHOMA CITY (AP) - The race for the top overall seed in the NBA playoffs is about to hit high gear.

When the Oklahoma City Thunder host the Miami Heat on Sunday for the first of two meetings over the next 11 days, it's the opening of what could be a critical stretch to determine who has home-court edge when the NBA finals roll around a few months from now.

The Thunder and Heat are in a virtual tie for second place in the NBA standings, 2½ games behind Chicago. The Bulls visit Oklahoma City next Sunday for the only meeting between those teams this season.

The two East leaders also have two head-to-head games remaining, one in Chicago on April 12 and one in Miami exactly one week later.

"The rest of these games that we're in are going to be tough. They're playoff teams - very, very tough teams," said James Harden, the Thunder's No. 3 scorer and top reserve.

"We're just going to have to go out there and do what we've been doing all season."

Until recently, at least.

Oklahoma City was leading the pack when the calendar flipped over to March but since then, it has been the Bulls who have pulled ahead despite the absence of reigning MVP Derrick Rose.

The Thunder went 5-5 over a 10-game stretch before winning back-to-back games against the Los Angeles Clippers and Minnesota, needing double overtime to eke out a 149-140 win against the Timberwolves without Ricky Rubio, second-leading scorer Nikola Pekovic and Michael Beasley.

Between the two showdowns with the Heat, Oklahoma City also faces a trip to Staples Center to face the Los Angeles Lakers and will host Memphis, the No. 4 team in the West.

"You always want to play good basketball against the best teams in the league and we have that opportunity ... to play playoff-type games in March," coach Scott Brooks said. "We're going to use that to our advantage.

"We know that this part of the schedule is going to be tough but we've played good basketball all year. We've just got to keep getting better. Being the No. 1 seed, we're not focused on that. We're focused on just keep getting better."

Last year, neither No. 1 seed made it to the NBA finals. Top-seeded San Antonio didn't even make it out of the first round of the Western Conference playoffs.

Miami ended up behind Chicago in the East standings last year, then beat the Bulls in the conference finals despite lacking home-court advantage. The Heat then lost to Dallas in the NBA finals despite having the home-court edge.

"Obviously, last year, we worked hard and we had the home-court advantage in the finals. That's what you work for," Dwyane Wade said. "If we take care of our job, it's a different story.

"Winning at home is very important. And obviously winning on the road is key."

The Heat have the league's best home record at 20-2, having won the last 14 in a row. Chicago is the NBA's best road team, at 20-6.

Oklahoma City also won 14 straight at home earlier this season, before losing three of four - to Cleveland, Houston and San Antonio - in March.

Combined, the three front-runners are 60-10 at home this season.

"It's important, but it's not the end of the world because there's only one (top) overall seed in the playoffs," Miami's Chris Bosh said. "You can't say, 'Oh, well, we're No. 2. It's over.'

"I think once you get to a certain part in the playoffs, everybody's a good road team, everybody's a good home team, so it's kind of neutral a little bit. But if it does come down to it, for a Game 7, you'd rather be at home."

Long before then, the Heat and Thunder head into Sunday's matchup trying to build momentum in the final stretch before the playoffs. Miami coach Erik Spoelstra wants more consistency from his team, at home and on the road.

Brooks wants to see improvement from a defense that has fallen to 18th in the league in points allowed - starting Sunday against the dynamic trio of LeBron James, Wade and Bosh.

"We know that we're going to have to do a better job of guarding those three players, but they have more than just three players," Brooks said. "They have a team full of good players that understand their role, and they don't have the record that they have by just having three good players. They have a good team."

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AP Sports Writer Tim Reynolds contributed to this report from Miami.