Short-handed Celtics steal win from sloppy Thunder

BOSTON -- With 20 seconds left Tuesday night, the Oklahoma City Thunder led the Boston Celtics by six. And, well, spoiler alert, the Celtics won the game.

The road to what could be a costly collapse by the Thunder was pretty straightforward, too. It started with Jayson Tatum finishing a mostly uncontested layup, then Russell Westbrook split two free throws with 16.8 seconds left to give OKC a five-point lead. The Celtics' Terry Rozier drilled an open, but very deep, 3-pointer, then Carmelo Anthony missed both free throws, setting up what felt like the inevitable.

It really was just a matter of who was going to hit the game-winning 3 for the Celtics -- Al Horford felt like the most likely…