stop thinking about guarding Dirk and work on frustrating him.
Gasol should technically be able to guard him in the post, but what happens if he's out on the perimeter?
You should have had Noah on him from the jump. Switch up your double team calls and make him have to pass out. Don't do it every time, but do it enough so that if he doesn't see it coming, he starts to rush with his offense hoping he can get a shot off before you bring it.
The goal with Dirk isn't to block his shots. You just need to bump and push him.
You gave up 28 points off of 14-18 shooting, which probably opened up the door for his teammates.
shoot for jumping, josteling, pinching, pushing...that nets you 21 points and 7-25 shooting. Send him to the line, try and punish him...and if you can..throw a little psychology in there because when superstars are having bad nights, it's really easy for users to get hard headed and keep shooting with them only to make it worse.