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Two of the NBA's most successful franchises, not just during this regular season, but over the past 15 years, will square off in the NBA Finals, starting Thursday night.

The Eastern Conference champion Miami Heat, who also double as the defending NBA champion, will have home-court advantage over the Western Conference winners, the San Antonio Spurs.

The Heat finished with the NBA's best regular-season mark, a staggering 66-16, which featured a 27-game winning streak, the second-longest in the history of the league.

The Spurs, who haven't played since sweeping the Memphis Grizzlies a week ago Monday, had the third-best record in the NBA at 58-24. If not for a Tony Parker ankle injury late in the season, San Antonio might have earned the next-best record behind the Heat.

But one season hardly makes for a successful franchise. The measure of greatness in professional basketball can be counted by the number of Larry O'Brien Trophies in team headquarters.

The Heat won last season's title and lost in the Finals the previous year. The Spurs have four championships since 1999, with the last coming in 2007. That year, San Antonio knocked off a young Cleveland Cavaliers team led by LeBron James.

Fast-forward to June of 2013 and James is already staking claim to the title of one of the best players in NBA history. He's won four MVPs, including the last two, and is a much more seasoned force.

"Just smarter, a lot smarter, more experienced, older, more mature both on and off the floor," James said on Wednesday. "And I think that's the most important thing. I've matured as a basketball player. I've matured as a man. And it has allowed my game to sprout."

It surely has and James' confidence has sprouted along with his game. There's also nothing wrong with James' memory, especially when it came to that first brush with the NBA Finals.

"When I got the ball, they kept me on the sideline. They went under a lot of my pick-and-rolls and dared me to shoot," explained James. "If you go into my pick-and-roll now, I'm going to shoot," he said. "And I'm confident I'm going to make every last one of them. I'm just more confident in my ability to shoot the ball.

"You can't dare me to do anything I don't want to do in 2013."

Bold words from the game's best.

Another difference between the Finals six years ago and now has to do with James' supporting cast. Cleveland started James, Daniel Gibson, Drew Gooden, Sasha Pavlovic and Zydrunas Ilgauskas. Miami features Hall of Famers-in-wait in Dwyane Wade and Chris Bosh, but that duo may hold the key to the series.

Both struggled badly against the Indiana Pacers in the Eastern Conference Finals. Wade averaged 15.4 ppg during the Indiana series and his knee is nowhere in the vicinity of healthy. But, with everything at stake, Wade had 21 points in Game 7.

Bosh has been really bad of late. He hasn't scored in double figures since Game 3 against the Pacers and had a very difficult time matching up physically with both Roy Hibbert and David West. Things don't get easier against San Antonio where he'll either have to defend Tim Duncan or Tiago Splitter, who is much bigger and stronger.

And what about Duncan. The three-time Finals MVP, enjoyed a career renaissance this season. After shedding 25 pounds in the offseason, Duncan averaged 17.8 ppg, 9.9 rpg and 2.7 bpg. He returned to the All-NBA First Team for the first time since the 2006-07 season and was Second-Team All-Defensive.

Duncan was not alone in getting San Antonio back to the Finals.

Parker was his consistently great self in the regular season, but his scoring is up almost 3.0 ppg during the postseason. He's at 23.0 ppg throughout the playoffs and was legitimate MVP candidate before an ankle injury.

Manu Ginobili is the third member of San Antonio's version of the Big Three. He has struggled shooting during the postseason (38 percent from the field and 32 percent from the 3-point line.)

Duncan, Parker and Ginobili have combined for 98 playoff victories. That total is second all-time to the Los Angeles Lakers' trio of Magic Johnson, Kareem Abdul-Jabbar and Michael Cooper.

Duncan, Parker and Ginobili have played 150 playoff games together. That is 72 more than the next highest trio of active players -- Boston's Paul Pierce, Kevin Garnett and Rajon Rondo. (Wade, Udonis Haslem and Mario Chalmers are third with 69.)

"We've been blessed to have won four championships. And we're blessed to be back and have a chance to win the fifth one," said Duncan. "So it doesn't matter what people say or what people think or how they take us, as long as we're in the mix when we have to. And we're back here right now to make another push at it. So that's all that matters to us."

These teams are both so strong and sadly, the head-to-head regular-season matchups offer little insight.

Spurs head coach Gregg Popovich, who can join Pat Riley and John Kundla in third place in NBA titles as a coach, famously sent Duncan, Parker, Ginobili and Danny Green home the day of the first regular-season matchup in Miami. The NBA fined the Spurs $250,000 for the action, but the Heat barely squeaked out the victory.

In the second regular-season meeting, this time in Alamo City, the Heat clinched the best record in the league and sat James and Wade. Miami still prevailed.

"They're still the defending champs. They're still the best in the regular season," Duncan said.

And the respect goes both ways.

"They've got a bunch of Hall-of-Famers, so I look forward to the challenge," James said.

Game 2 will be Sunday night in Miami.