SAN ANTONIO -- Tim Duncan is still trying to figure out what hit him -- and why.

LeBron James and the Miami Heat are simply on edge.

Blame it on their inner Floyd Mayweather that has the Heat getting defensive about the slightest perceived, well, slights these days. It’s an attitude that’s eight months in the making. The two-time defending champions have reached the point after four straight trips to the NBA Finals that just going out and trying to win for the sake of winning is not only expected, it’s boring.

Why not shake things up, at least for show?

So when Duncan, the most decorated power forward in NBA history, suggested his San Antonio Spurs wouldn’t squander another opportunity to beat the Heat this time in the Finals that open with Game 1 on Thursday, it was akin to tossing raw meat into the lion’s den at a local zoo.

Never mind that, in reality, it was processed food. Technically, Duncan’s comments, which came immediately after San Antonio put away Oklahoma City in the Western Conference finals last week to set up the rematch with the Heat, were benign and far from legitimate bulletin-board material.

Yet still, the Heat parlayed it into motivational meat -- with James, Dwyane Wade and Chris Bosh feasting on the manufactured disrespect from a Spurs team that had Miami in a 3-2 series deficit and was 28 seconds away from securing the fifth title in franchise history last June.

"Everybody keeps talking about it," Duncan said Wednesday. "I don't know [if] what I said was so bad. I said I wanted to win the Finals. We're back here now, and I wanted to win. If they need to find fuel in that, so be it."

At this stage, those are fighting words for Miami.

"I can't sit here and lie to you," James said Wednesday of the perception Miami was gifted a title last season by a fluky Spurs collapse in Game 6, followed by another close loss in Game 7. "We feel slighted. It went seven. It wasn't like it was 3-0 and they had us in Game 4 and we took it and won four straight."

Two of the most respected and professional franchises in the NBA have traded some barbs that have turned a Finals rematch in basketball into one that feels like the prefight buildup to one in boxing.

So it's only fitting some members of the Heat continue to draw inspiration from a message Mayweather delivered to the team during a preseason visit that was arranged after he received a text from James. If there has been a collective chip on the Heat's shoulder as of late, it was placed there by the most polarizing boxer in the game eight months ago and has reemerged at the peak of the postseason.

"Basically, what I told LeBron and the team is that these guys are going to be gunning for you because you're world champions and people are coming for that throne," Mayweather said during a conference call about the Heat's quest for a third straight title. "I told them back then that each step was going to be rougher and rougher, and you have to get tougher to stay in this position."

If the Heat, collectively, were a prizefighter, they'd be Mayweather -- the "Pound for Pound" king of his sport who is as divisive among global fans as he is dominant in the ring. The flamboyant Mayweather remains undefeated through 46 fights and has defended titles in five weight classes.

Mayweather has attended Heat games during the playoffs and was at AmericanAirlines Arena to watch Miami’s most impressive performance of the postseason when they routed Indiana by 25 points in Game 6 last week to advance to the Finals.

As the Heat prepared to sharpen their title defense entering the season, they reached out to Mayweather, who recently recalled several points he made during his brief time with the team.

"Man, it's a lot of similarities," Mayweather said of the way he and the Heat have to deal with critics. "But it's different also because these guys are a team. With me, it's a one-on-one battle. But if the team loses, you realize still, LeBron James is going to have to take all the slack ... no different from a fighter."

Each round of the playoffs has brought out more feistiness from the Heat.

It started against Charlotte, when James was rocked as he drove to the basket by a forearm shot to the neck late in Game 2 by forward Josh McRoberts. James responded by averaging 30.5 points, 8.5 rebounds and 7.5 assists in the final two games to complete a 4-0 sweep in the first round.

In the second round against Brooklyn, James and the Heat scoffed at some of the tough talk from Nets forward Paul Pierce. James also laughed off rumors that he had an altercation with Pierce and the two had to be separated in the tunnels of the Barclays Center after a game in Brooklyn.

James countered with a 49-point effort in Game 4 and combined with Wade for 57 points, 11 rebounds and eight assists to eliminate the Nets a game later in Miami. Miami then answered the irritating antics of Indiana's Lance Stephenson by annihilating the Pacers to close out the series in six games.

Veteran Heat forward Udonis Haslem, considered the team's resident enforcer, said he has carried one story from Mayweather's early-season testimony with him into the postseason. Mayweather told the Heat how he was nearly knocked out on his feet by a punch from Shane Mosley in the second round of their 2010 fight. It took Mayweather several rounds to recover before he won a unanimous decision.

"I remember him saying that was probably the closest he's ever been to being knocked out in a title fight," Haslem said. "We've been there before, too. He took a good hit. He was dazed a little bit. But he got himself together, finished the fight and won the fight. That's the same thing with us. It's been a long season to get back here. We've taken some hits. At times, we might have looked dazed a little bit, but as champions, you get up, keep going and get the job done. And that's what we're going to try to do."

Mayweather sees the spirit of a sharp fighter in the Heat after all their battles.

"You don't stay on top by keep doing things one way," he said. "You have to make adjustments and always be ready to adapt to many styles. That's basically what I told them."

The Heat apparently listened and applied those lessons all these months later.

Much like Mayweather, they don't just take on good fights; they have a flair for finishing them.

Even if it requires a bit of manufactured motivation to remain on edge in the Finals.