Russell Westbrook sparked the Thunder in Game 5. (Getty Images)

OKLAHOMA CITY -- The tone was set well before tip-off.

A couple Thunder players sat at their lockers roughly 90 minutes before they took on the Lakers in a potentially clinching Game 5. But instead of tuning out everyone around by having headphones on, they traded lines from the movie Superbad.

You could call it staying loose, being confident or whatever, but the Thunder weren't stressing over Game 5. They were doing what they do.

The Thunder locker room is a fun place to be before tip-off. Jokes are flying, players are making fun of each other and movie lines are being recited. This team acts their age in that locker room. They seem like a bunch of kids -- inexperienced, raw and immature. Until they step out on to the basketball court. Then it's all business.

Consider this: Against the championship tested Lakers, the Thunder won the five fourth quarters in the series 119-97 -- and 93-67 in the four wins. Twice the Thunder came back from fourth-quarter deficits to win. Twice it was Kevin Durant, not Kobe Bryant, doing the closing. The Thunder have a look in their eyes and it's obvious -- they're ready to gut you, and they're going to have fun doing it.

It's that confidence, that bravado, that swagger the Thunder carry around that makes them such a difficult team to control. Kobe talked about how OKC can "blitz" you with big runs and it happens because they're always remaining loose. They let pressure slide off their backs. Instead of tightening, they embrace the big moment. They stay composed, calm and confident.

"I'm very proud of the Thunder, just from top to bottom," said James Harden. "Russell in the second half was amazing. The bigs' defense was phenomenal. KD hit two bigs 3s. The team effort was amazing and we needed it."

The Lakers were hanging tough in Game 5 as Kobe poured in points. The Thunder appeared to be heading for another difficult final 12 minutes. And then the explosion happend. Nick Collison put back a miss with a dunk. Russell Westbrook hit a circus and-1. Kevin Durant started the fourth with a couple 3-pointers. The onslaught was on and there was nothing the Lakers could do to stop it.

"We know that is the most important part of the game and I think we kept our composure in the fourth quarter and made plays on the defensive end as well as the offensive end," Durant said. "And we believe, even if we're down or even have a lead, we still wanted to play the right way and the right basketball."

That kind of mindset will come in handy as the Thunder get set to take on an even more experienced, seasoned group in the Spurs. It's a master versus pupil matchup. The Spurs are the original Thunder, a small market team built from the ground up that sustained success. They play as a team, falling lock step in line behind their leader, Tim Duncan.

But I doubt they're in the locker room saying things like, "McLovin? What kind of a stupid name is that? What are you trying to be, an Irish R&B singer?"

It's a second straight trip to the Western Conference finals for the Thunder and they'd like to tell you that they're a long way removed from the collapses against the Mavericks last season. They've learned, grown, gotten bettter and matured. Everywhere, except off the court.