I didn't see the whole game but the Piston's defense was outstanding from what I saw. There has definitely been a culture shift where all five guys on the court are working hard on defense a lot more than most NBA teams. Stewart and Ausar set the tone. Obviously, the coaches deserve a lot of credit. And having meaningful games is a big part of it also.
It's too bad Steph banked in that three late in the game. That was probably the difference.