One play summed up the Celtics’ worst loss of the season. One that followed a road trip filled with hope for a turnaround, even if it featured a letdown against the Thunder, Boston’s likely top rival in the title race. Jrue Holiday and Jaylen Brown both floated away from Malik Monk after he swung the ball to his right. The ball returned to Monk and all five Celtics players stood in place and stopped moving. The shot bounced back to Domantas Sabonis, and again, nobody flinched as he knocked down the shot. “Some plays, it just happens,” Kristaps Porziņģis said. “It’s not like we’re not trying. It’s like, I’m thinking this guy’s going, I’m not going and then we just stay in the same place, and it doesn’t look perfect. But we’re gonna get past it. We’re gonna be fine.”