To me, the game plan against the Rockets is: play Harden straight up, don't foul, don't help. He can get his, try to minimize sending him to the line. Foul any of their bigs, including Howard, they're all below average free throw shooters. And then stay on the rest of their guys and minimize their damage. The rest of that team can't get past anybody on a dribble drive, nor post up. Get back in transition, since Brewer and Terry like to leak out for the open court drive or 3 pointer.
There's some difficulty for the Spurs because we're over eager to help, and this is a situation where you don't want to do that. But with proper execution, there's nothing more to it, IMO.