OKLAHOMA CITY -- Before the Dallas Mavericks tipped off in a crucial playoff game Monday night, team owner Mark Cuban decided to add a little spice to an already burning series with the Oklahoma City Thunder.

The outspoken Cuban told reporters that Thunder point guard Russell Westbrook was just an All-Star and not a superstar.

For most players, the comment would just be background noise. For someone like Westbrook, it was lighter fluid for an already burning motor.

Westbrook helped end the Mavericks' season, leading the Thunder to an 118-104 victory in Game 5 of the Western Conference first-round playoff series at the Chesapeake Energy Arena.

Westbrook was asked after the game to respond to Cuban's comments. Thunder teammate Kevin Durant jumped in with an assist.

"He's an idiot," Durant said of Cuban. "He's idiot. That's what we've got to say about that. Next question."

Oklahoma City won the series 4-1 to advance to a Western Conference semifinal against the Spurs. Game 1 will be Saturday at San Antonio.

Westbrook racked up 36 points, 12 rebounds and nine assists Monday, shooting 13-for-23 from the floor. Durant scored 33 points on 11-of-24 shooting to go along with seven rebounds. Steven Adams added 15 points and 10 boards.

"I will tell you this, I'm happy he's on my team," Oklahoma City coach Billy Donovan said of Westbrook. "I wouldn't trade him for anybody. There is no question that Russell Westbrook is one of the best players in this league."

Dirk Nowitzki paced Dallas with 24 points on 8-of-16 shooting. Dwight Powell came off the bench to score 16 points and grab nine rebounds. Justin Anderson added 14 points in the loss.

"We're disappointed at the result, obviously," Dallas coach Rick Carlisle said. "But I thought the effort from our team, from start to finish in this series, was second to none. Couldn't be prouder of the way our guys competed all the way up to the last second in our final game."

With 7:50 left in the game, Nowitzki cut the Thunder's lead to 101-98. Dallas got the ball back but missed two open 3-pointers that would have tied the game.

Westbrook was fouled and hit a pair of free throws. After Dallas' J.J. Barea missed a jumper, Westbrook drained another shot to put the Thunder up 105-98.

Oklahoma City's Andre Roberson came up with a block, and it led to another Westbrook jumper with 5:05 left.

The Mavericks' Raymond Felton finally ended the run with an off-balance bucket. Dallas got the ball back, and Nowitzki drained a 3-pointer from the corner.

Westbrook took a long 3-point attempt that was off target. Roberson got the rebound and scored on a put-back.

On their next possession, the Thunder missed three shots but got the rebound each time. Durant finally knocked down a mid-range jumper and was fouled in the process. Nowitzki was called for a technical foul. The ensuing free throws gave the Thunder an 113-103 lead with 2:49 left. That was enough to put the game and series away.

"I think for us getting a chance to move on is great," Donovan said. "I think this series made our team better. We dealt with a lot of physical confrontation. I say that in a very positive way."

Westbrook began the night like a man on a mission. Whether it was knocking down his jumper or driving the baseline for dunks, he had the Dallas defense on its heels. He ended the opening quarter with 13 points on 5-of-8 shooting.

Westbrook's attack mode may have been inspired by another confrontation with Dallas forward Charlie Villanueva during his pregame dance.

"Now he gets to go home and get ready in the offseason to sit and watch 82 more games like he did this year," Westbrook said of Villanueva.

"He might not even be in the league," Durant added.

Oklahoma City pushed its lead to 13 points before Dallas began to whittle it down. Led by Nowitzki, the Mavs got the deficit down to a single basket with 2:32 left in the first half.

However, the Thunder outscored the Mavs 13-8 down the stretch and grabbed a 68-61 halftime advantage.

Oklahoma City was unable to pull away for much of the second half. Every time, Durant, Westbrook or Dion Waiters put the home team ahead by more than 10, the Mavs found a way to claw back to within striking distance. Despite having only 10 players in uniform, the Mavericks kept on battling back.

"Metaphorically, we emptied our chamber in five games," Carlisle said. "I don't know what we would have thrown at them in Game 6. They were just simply better. Their two superstars were just great this series."

NOTES: Dallas F David Lee missed Monday's game due to a right heel injury. He played through the pain in Games 3 and 4 but was in a walking boot Monday. ... Dallas C Salah Mejri sat out Monday due to with a hip flexor injury. "I don't think there was any setback," Dallas coach Rick Carlisle said. "He got his hip wrenched the other night or strained. He did a few things this morning and tried to warm up. He's not going to be able to go and help us." ... Dallas G Deron Williams was out for Game 5 due to a sports hernia. ... Even though Oklahoma City F Kevin Durant isn't having a great postseason in terms of scoring, Thunder coach Billy Donovan said he adds more to the game than points. "I think the one thing for me with Kevin that I've always tried to explain to him, and he's been great with this, there is so much more to his game," Donovan said. "I think he's rebounded the ball better, his assists are up. I think there's a lot of different ways he can impact the game."