Mario Chalmers Growing From Heat's Weak Link to Clutch Hero in NBA FinalsMario Chalmers is a grown man. He may be the "little brother" who LeBron James, Dwyane Wade and Chris Bosh tease like they would a younger sibling, but he is 26 years old, a four-year NBA veteran and a father.

Most importantly from the Miami Heat's standpoint, he is a man who has helped them move within one game of winning an NBA championship.

When James was struck by debilitating leg cramps late in Game 4, the player to come to Miami's rescue offensively was not Wade or Bosh. It was Chalmers, who led all Heat players with 12 points in the fourth quarter and scored his team's final five points with James on the sideline.

The first thing anyone notices when they talk to Chalmers is that he carries himself like a star. His status as a former second-round draft pick on a team filled with superstars might lead one to assume he possesses an aw-shucks personality, but that is not the case. When the Thunder assigned Kevin Durant to guard him, he was offended, because he knew what it meant. Thunder coach Scott Brooks did not place Durant on Chalmers because he was worried about stopping the Heat point guard. Brooks made the move because he wanted Durant to help off Chalmers, who struggled with his shooting in the first three games of the series.

"Yeah, I took it as a sign of disrespect," Chalmers told reporters after Tuesday's game.

This is the guy, after all, who hit that dramatic 3-pointer for Kansas to force overtime in the 2008 NCAA Championship game. Wade called Chalmers, simply, "a winner," and with a second look at Chalmers' fourth quarter in Game 4, it is difficult to come to a different conclusion.

Only two players never left the floor for the Heat in the final 12 minutes of Game 4: Wade and Chalmers. With James sidelined, the surprise closer was Chalmers, who hit four of the five shots he took and iced the game with two clutch free throws after Russell Westbrook's immediately infamous foul. Chalmers committed only one turnover in the final quarter and none in the final four minutes.

Chalmers' perception of the Thunder's defensive mindset — that his opponent was not convinced he could, or would even try to, score in the clutch — appeared to be dead on. After getting a fresh possession early in the fourth thanks to James Jones' offensive rebound on a missed three by James, Chalmers dribbled the ball on the right wing and sized up Westbrook, who was guarding him. Westbrook did not seem committed to covering him, as though Westbrook anticipated Chalmers hastily giving up the ball. So Chalmers gave a slight shimmy and cruised to the hoop for a relatively uncontested layup.

The fourth quarter was filled with moments like those, when the Thunder gambled on Chalmers being unable to play the hero and Chalmers repeatedly proved them wrong. As if to drive home the point that they did not fear Chalmers, the Thunder also defended him with 37-year-old Derek Fisher for a sizable stretch. Needless to say, Chalmers won that battle, too.

Once Chalmers was done blowing up Sixth Man of the Year James Harden, five-time league champion Fisher and three-time scoring champ Durant, he had an opportunity to gloat. Here was where a true little brother would have puffed out his chest and unleashed his stream of trash talk to remind his big brothers that he was not so small and weak anymore.

Yet Chalmers did not even muster a smile for his postgame interview. He still had business to attend to, like any grown-up.

"We've got one more win," Chalmers said. "We want to take care of business, and after we get that last win, I can be all smiles."

Winning a championship makes kids out of everyone. Until then, Chalmers will try to continue to make dicing up the Thunder's defense look like child's play.

Have a question for Ben Watanabe? Send it to him via Twitter at @BenjeeBallgame or send it here.