PHILADELPHIA — Once again, the Thunder played much better defense late than early. Once again, no one on the team seemed to know why. And once again, OKC won in overtime. The Thunder overcame a five-point deficit in the final 36.9 seconds of regulation and went on to post a 110-105 victory over the surging Philadelphia 76ers before a crowd of 19,283 at the Wells Fargo Center. It was the second overtime victory this week for the Thunder, which is now 7-1 in extra time this season. "Down by five, then get lucky to win the game," Thunder coach Scott Brooks said afterward. "I'm not happy with that (slow starts defensively), but I love the fact that as the game goes on, the competitive spirit rises with this group. That's been our season all along, but we need to get better starts defensively." OKC got some clutch shooting from All-Stars Kevin Durant and Russell Westbrook, plus a double-double off the bench from Nick Collison (13 points and 10 rebounds). Durant forced overtime by draining a 3-pointer with 6.2 seconds left, then nearly won the game at the final buzzer in regulation from almost the exact same spot on the left wing. "Coach drew up some great plays," Durant said. "I was able to get open and make a few shots." Though Durant was superb offensively with 34 points, it was his 16 rebounds that kept the Thunder (40-23) within reach in the early going. Westbrook had 27 points and 12 assists, but it was him taking a charging foul underneath the basket off a barreling Andre Iguodala with 1.9 seconds left in regulation that clinched no worse than overtime for OKC. "He (Durant) and Westbrook are something special," Sixers coach Doug Collins said. "Westbrook is a dynamite package. He is so strong and quick. Durant, just the reach on his shot … He made an incredible shot." The Sixers (33-31) jumped out to a 15-4 lead and led 34-28 after the first quarter thanks primarily to 6-of-9 shooting from 3-point range. From that point forward, OKC allowed 71 points in the final 41 minutes. "We were just trying to get stops and worry about the offense later," Durant said. The Sixers went scoreless in the final 2:19 of regulation and managed just four points in the five-minute overtime. They were 10 of 18 from 3-point range in the closing minutes of regulation, but missed their final six attempts beyond the arc. "I thought that was as good a defense as we could play in the second half," Brooks said, for the umpteenth time this season. "Everybody jumped in there and committed to it. We got a big win. You need a lot of things to go your way and you need some help or some good fortune, and we got it." The Thunder created some of its own luck with relentless hustle on defense, particularly when almost all hope seemed gone. "Yeah, man, it was looking bad for us for a minute," Durant said. "We stayed with it. We got some stops. That's a good thing we did late in the game, was get some stops." As for his team's penchant for winning in overtime, Brooks smiled and said, "That's pretty good. We have good players in overtime making shots. We have some shot-makers who love big moments." Durant said of working overtime: "We know how to handle those situations. We're very patient." The Sixers came in having won three straight, seven of their last eight and 16 of their last 21 games. "That is the first one that had gotten away from us in a long time," Collins said. "Durant had to hit a hell of a shot to get it into overtime." The Thunder returns home for a Friday game against Detroit, then departs for a three-game road trip next week at Cleveland, Washington and Miami.