I reckon that's 4th quarter fatigue that's to be expected to be fair. They're effectively playing with 2 guys right now, so it's not surprising that they can't sustain that heat for 4 quarters.
Yes, I suppose that's part of it, but I think Warriors actually might've showed in that Q4 a possible solution to the Della problem as well by using Lee to set the high picks for Curry. Thompson ended up matched against Curry and Della against Lee several times in that quarter, which is what the Warriors would love - no question who won that matchup there.
You can see highlights for Q4 again here:
I'm surprised the Warriors haven't tried to run Della through more screens though to help Curry shake him, or even just to wear Della down. He's the Cav's trump card right now, and if the Warriors can wear him down more over the course of a game, they'll have a good chance to neutralize or at least reduce the influence he's had on this series.
I have to say again that Tristan Thompson is really coming up big in this series with his offensive rebounding. He's taking rebounds from the Warriors' bigs like a man swiping candy from kids. Bogut has been a huge disappointment this series for the Warriors, and Ezeli seems to have small hands for a big man as he struggles to hold onto a rebound.
Hat-tip to these Cavs - they're playing with more heart and a lot more aggression right now and deserve to have the series lead.
I'd like to see Kerr go with the Splash Bros, Iguodala, Lee and Ezeli to start Game 4. Use Green's energy to spark them off the bench and rotate with Iguodala on James. Give the Cavs a different matchup to ponder from the start.