With 41.7 seconds left Sunday night and the Thunder leading 93-90 against Toronto, center Kendrick Perkins was fouled while grabbing an offensive rebound.
Perkins missed both free throws, and the Thunder never scored again in a 95-93 loss.
"When you end a two-point game like that, you can go through the game and pick out little details where you messed up. I'm talking about me personally," Perkins said. "It's one of those games where you just have to look yourself in the mirror and come back and be prepared to go against the Jazz for the next game (Wednesday).
"It was a tough loss. I obviously have to be better in certain situations. I think we can be better as a team, and me personally, I can be better."
Thunder coach Scott Brooks was asked if there was a decision to be made whether Perkins should play late in games because of his poor free-throw shooting. He is shooting 60.5 percent in his career from the free-throw line.
"I believe in Perk," Brooks said. "We have a good player who has a lot of experience. It's easy to point to that (missing two free throws), but it still comes down to we were up three. Could he have made one or two? Yes. Absolutely, but he has to go up there, shoot them with confidence."
Brooks and All-Star Kevin Durant agreed the Thunder's effort wasn't half-bad on Sunday.
"The defense was good," Durant said. "We couldn't get the other end going. It's one of those games you have to live with because we're a defensive team, but I wish we had more going on the offensive end. You've just got to learn from it. It's tough, it's tough. You've got to give those guys credit, though. They played hard all night, made it tough on us."