A pedestrian regular season doesn't mean that the reigning NBA champions are going down without a fight.

The Dallas Mavericks gave the uber-talented Oklahoma City Thunder all they could handle in the opener of their Western Conference quarterfinals set and will try to even things on Monday when they the two teams tip-off Game 2 in the Sooner State.

It wasn't easy, but the Thunder managed to take a 1-0 series lead on Saturday after an exciting back-and-forth final frame that ended with scoring champion Kevin Durant burying a game-winner with 1.5 seconds left to play in a 99-98 OKC win.

After 2010-11 NBA Finals MVP Dirk Nowitzki gave Dallas the lead with a pair of free throws with nine seconds remaining in the contest, Durant heaved a high-arcing, off-balance floater from the foul line over the outstretched arms of two Dallas defenders.

The ball bounced high off the front of the rim, tantalizing the Oklahoma City faithful before hitting off the backboard and through the net, sending the jubilant home crowd into complete euphoria.

"They switched back (Shawn) Marion on me and he's such a real good defender. And I just didn't want to settle for a three so I just tried to take it closer and shoot a shot. I got enough arc on it and it was able to fall in," Durant said of his game-winning shot.

Dallas, which was out of timeouts, could not get a shot off before the final buzzer.

Durant, who just became the seventh player in NBA history to win three straight scoring titles, finished the game with 25 points on 10-of-27 shooting to go with six rebounds and four blocks for the Thunder, who fell to the Mavericks in five games in last year's Western Conference Finals.

Russell Westbrook led all scorers with 28 points, while Serge Ibaka added 22 points and five blocks. James Harden made his first appearance since suffering a concussion after being elbowed by the Lakers' Metta World Peace last Sunday and scored 19 points off the bench.

Nowitzki netted 11 of his 25 points in the final five minutes to pace Dallas. Jason Terry buried four three-pointers en route to 20 points and Shawn Marion tallied 17.

"We were right there," Nowitzki said. "We made some mistakes, (we) turned the ball over twice in the last three minutes when we were up seven."

Oklahoma City took three of four against the Mavs in the regular season. These two franchises have met three times in the postseason, last year's matchup as well as in 1984 and '87 when the Thunder were known as the Seattle SuperSonics. Dallas won in '84 while Seattle rebounded in '87.

Game 3 of this best-of-seven series is set for Thursday in Dallas.