Gerald Wallace was wreaking havoc all over the Oklahoma City Arena floor, harassing All-Star Kevin Durant on defense and making seemingly every shot he took from everywhere he took it.

The Trail Blazers, after digging themselves an early hole, had clawed back into the game and were matching the Oklahoma City Thunder blow-for-blow. And with just over six minutes remaining in a pivotal Western Conference matchup, the score was tied 82-82, setting the scene for an anybody-can-win finish.

And then the inevitable unfolded Sunday night: The Thunder took over down the stretch, administering their third backhand slap to the Blazers this season in a 99-90 victory before a sellout crowd of 18,203.

"Most times you can look at a loss and try to take a positive out of it to keep your head up," said Wallace, after playing his best game in a Blazers uniform. "But in this situation, at this stage of the season, there's nothing positive about this. This was a game we should have won."

Instead, the Blazers (42-31) went to sleep in the wee hours this morning haunted by the clutch play of Russell Westbrook and knowing that they squandered their third winnable game against the Thunder (48-24), who clinched a playoff berth by winning for the 12th time in the last 14 games.

Westbrook, in a performance that was as good as any against the Blazers this season, scored 14 points over the final 7:11 of the game, punishing the Blazers with three clutch three-pointers that turned out to be the difference. Most of his shots came with the shot clock winding down and with a Blazer defenders in his face as he made 5 of 7 field goals in the fourth quarter.

He finished with 28 points, seven assists and seven rebounds -- and one Blazers beat-down.

"He was phenomenal," Blazers center Marcus Camby said. "He hit some big shots tonight."

The biggest came with 21.9 seconds remaining, when Westbrook swished a dagger three-pointer over the outstretched arms of Wesley Matthews to give the Thunder a 97-90 lead that iced the game.

Westbrook, who scored 11 of the Thunder's final 15 points, also hit back-to-back three-pointers during an 8-0 run midway through the fourth quarter after the Blazers had tied the game at 82-82.