Oklahoma City, which entered the game second in the NBA in free throw shooting at 81.8 percent, went 35 of 36 (97.2 percent). But the Thunder shot 37 percent from the field and scored a season-low 14 points in the fourth quarter.
Durant finished 5 of 16 from the field and committed six of the Thunder's 19 turnovers.
"Losses happen in this league," Durant said. "They beat us fair and square, you know? We missed some shots, too. I think our defense was good. They got some shots late in the fourth quarter that helped them a little bit but I think our defense was good. We were swarming them and they hit some tough ones, too, but we missed some good looks."
The Thunder, who have won 17 of their last 19 games, were coming off a win at San Antonio on Saturday night. Asked if the Thunder lacked energy down the stretch, Durant answered, "Nah."
Toronto went 7 of 14 from 3-point range and scored on its final nine possessions of the first half, turning a five-point deficit into a 62-56 halftime lead. The 62 points were the second-most surrendered in the first half this season by Oklahoma City.
Oklahoma City clamped down on defense in the third quarter, allowing the Raptors only 13 points, matching their season low for a quarter.
DeMar DeRozan added 17 points for Toronto and Valanciunas had 13.
Notes: Durant was called for a technical foul, his third of the season, while on the bench in the second quarter. Durant protested after a scramble for a loose ball between Oklahoma City's Nick Collison and Toronto's Valanciunas. Ironically, Valanciunas was called for a personal foul on the play that Durant protested . Toronto is 7-6 on the road. It's been since Feb. 25, 2008, that the Raptors have been above .500 on the road this late in the season . Thunder C Steven Adams picked up three fouls during a two-minute stint in the first quarter.