OAKLAND, Calif. -- Oklahoma City missed a golden opportunity to strengthen its playoff seeding heading into the final week of the regular season. Now the Thunder need some help to avoid a first-round matchup with the defending champion Lakers.
Kevin Durant scored 40 points and increased his lead over Cleveland's LeBron James in the NBA's scoring race, but the Thunder blew a 20-point lead and lost to the Golden State Warriors 120-117 on Sunday night.
The loss dropped the Thunder into the eighth seed in the Western Conference with two games remaining. Oklahoma City is tied for sixth with Portland and San Antonio, but the Blazers and Spurs hold the tiebreakers.
"When the playoff seeding takes shape I hope we don't look back at this game as the one that got away and affected us," Durant said after his team wasted a 20-point lead in the loss. "We all know the Western Conference is tough and we need to make sure we take care of games like this. It's a tough loss for us."
Oklahoma City can move out of the eighth spot by beating Portland at the Rose Garden on Monday night. The Thunder won there earlier this season but have lost twice at home to the Trail Blazers.
The Thunder had a chance to give themselves some breathing room and appeared headed for an early rout before the Warriors, sparked by the return of scoring leader Monta Ellis, stormed back to win.
Ellis scored 27 points in his first game following a two-week absence, Stephen Curry added 25 and Golden State won in its first home game since coach Don Nelson became the NBA's career victory leader.
"When you lose a game like this, especially in the Western Conference, it can drop you two to three spots," Thunder coach Scott Brooks said. "On the flip side, a win can push you up two or three spots as well. That's how important a game like this is."
Nelson was honored during a pregame ceremony commemorating his 1,333rd career victory last week, which moved him past Lenny Wilkens for the top spot on the NBA's wins list. Video tributes from fellow coaches Pat Riley, Larry Brown and others also played on the scoreboard hanging above midcourt throughout the game.
This will be one Nelson remembers for a long time, even though he let assistant Keith Smart handle the coaching duties for the game.
"The way it looked to start the game off, I thought it was going to be one of those long nights," Smart said. "We kind of went small a little bit. We had guys on the floor that I thought could help open the floor."
Oklahoma City's focus, though, was on the playoffs and Durant's pursuit of the NBA's scoring title.
The second-year forward topped the 30-point plateau for the 45th time this season -- tops in the NBA -- while improving his average to 30.1 points. James, who sat out his third straight game in the Cavs' 98-92 loss to Orlando on Sunday, is at 29.7.
With Portland beating the Lakers earlier in the day, the Thunder needed to beat Golden State to hang onto their one-game lead for the sixth seed. Instead, after scoring 31 points in the first 7 minutes, Oklahoma City's offense went cold while allowing the Warriors to post their second-largest comeback of the season.
Both Ellis and Curry missed key free throws in the final 29 seconds, but the Thunder committed two turnovers and couldn't get off an uncontested shot over the final 1:11.
"We really weren't focusing on anything behind us," said Ellis, who was 10 of 21 from the floor. "That's why we've been playing the way we've been playing. We'll go down in history as the team that gave [Nelson] that record so that's a good thing but the positive thing is everybody's playing together and having fun."
The Warriors missed three free throws in the final 53 seconds but held on to win when Durant's 3-point attempt with a second left bounced off the back of the rim.
Durant had 18 in the first quarter but scored sporadically after that, finishing 13 of 29 from the floor -- including 3 of 8 from 3-point range.
Ellis scored nine straight points in the fourth quarter, including a 3-pointer that gave Golden State a 111-109 lead. Durant answered with a 21-foot jumper to tie the game but the Warriors made five free throws down the stretch to seal the win.
The Thunder need one victory to reach the 50-win mark for the first time since 2004-05 when the franchise was in Seattle. That was also the last year the team made the playoffs. ... Oklahoma City failed to sweep the four-game season-series from Golden State, losing at Oracle Arena since Feb. 21, 2009.