A few things jumped out at me:
We had 46 points in the paint to their 48 so we were attacking the basket, yet we had 11 fts to their 36 fts.......that's a huge deciding factor in the game. This is where the game was won. (although the last 6ft's were intentional fouls, but it's still a huge discrepency).
Barbosa struggled bigtime, made poor decisions, took poor shots and missed them. He had some good moments too and hit a few threes, but he was forcing things rather than playing within his abilities (trying to shoot a 20ft shot over 7ft Dirk isn't smart).
James Jones played good defense and had 6 blocks in limited minutes and those blocks were on Dallas layups and putbacks.
Marion had 19pts & 19 rebs, but was almost invisible in the game. He needed to take more of a role offensively especially with Howard, KVH or Dirk trying to guard him.
Diaw is still showing how great he's going to be, but his defense on Josh Howard is horrible. We need to switch Marion onto Howard and let Diaw try to guard Dirk for a while. Diaw's actually got more length to bother Dirk and his slower foot speed won't be abused by Dirk as much as Howard is abusing him.
Our most productive lineup was when we played big with Nash, JR, Diaw, Marion, TT.
Diop really changed the game for Dallas, they let him loose to go after rebounds with reckless abandon. He was the only Mav going after offensive boards and was able to tip the ball and get Dallas more possessions (although he was constantly over the back and pushing people out of the way to get those rebounds and tips).