Year Two of the "Big Three" era in Miami has the Heat competing for the National Basketball Association (NBA) title for a second consecutive year.

But rather than sheer elation over their Eastern Conference dominance, the pressure lies heavy on the Heat and their trio of three-time NBA Most Valuable player LeBron James and fellow All-Stars Dwyane Wade and Chris Bosh.

Anything less than an championship triumph over the Oklahoma City Thunder will be viewed as a failure for the threesome, who promised a string of NBA titles after deciding as free agents to join forces in South Beach.

James told a welcoming rally full of smoke and flashing lights two years ago that he and his partners would bring "not one, not two, not three, not four, not five, not six" titles, to rapturous cheers from the Heat faithful.

That helped cast the team, and King James in particular, as villains booed at every NBA road stop.

Last year, the Heat struggled to find their game-closing formula, undecided about which of their celebrated troika would take the big shots at the end.

Still, they made it to the finals against Dirk Nowitzki and the Dallas Mavericks before coming up short of their goal to bring Miami their second NBA title following the one that Wade won with the team in 2006.

Striving to improve his game despite being widely considered the world's best all-round player, James worked with Hall of Famer Hakeem Olajuwon to improve his post-up moves and the dividends were on glorious display in a monumental performance in Game Six of the Eastern Conference finals.

James worked inside to perfection against the Celtics and, on the brink of elimination, he spun to the basket for layups and dunks and sank a string of turnaround jump shots from all angles in scoring 45 points while pulling down 15 rebounds to save Miami's playoff run.

In wrapping up the series win over Boston on Saturday, James, Wade and Bosh, hitting full stride after being sidelined due to an abdominal strain, combined to score all of the Heat's 28 fourth-quarter points in turning a tight game into a rout.

Yet over time, the pecking order of the Heat has become clear. No longer is indecision and second-guessing rife on the team. James has taken charge and accepted the crunch-time load for the Heat.

"He is the leader of the team," Wade said about James following the Game Seven victory.

Said Bosh: "He's the best basketball player in the world."

The Heat beat the New York Knicks in five games, the Indiana Pacers in six games and went seven to dispatch the Celtics.

Miami and Oklahoma City split their season series 1-1 with each club winning at home.

Now the Heat, a 1988 NBA expansion team, set out for their second title when the best-of-seven series begins Tuesday in Oklahoma City and, fairly or unfairly, anything less will be seen as a failure for the franchise.

(Reporting by Larry Fine in New York; Editing by Frank Pingue)