All of Dirk Nowitski's wimpiness was on display in this game. I don't mean fear of physical pain. Nowitski is tough and stoic about physical pain - he does not fear it.
I mean, first of all, Nowitski's insistence on playing pure offensive basketball via driving to the basket and seeking shots - as opposed to seeking to draw body contact fouls. Playoffs drives to the basket are about throwing your body into the opponent and drawing the foul. Period. You draw the body contact and the foul first, then release the shot as an afterthought. If you attempt - first and foremost - to go for the shot, all of the following conspires against your success at making the shot: the athleticism of the defenders, the defenders' super playoffs focus on playing aggressive defense (which especially eliminates clever finger rolls, i.e. cheap shit), playoffs refereeing which allows aggressive play when going for blocked shots. It's too much to overcome. The only persons who can consistently fight this and put the ball in the basket are rare power players who can power through defenders for dunks: Shaq; Amare Stoudemire. Consider Tim Duncan in the playoffs: he has the bank shot; every other move he makes is designed to set up body contact. Tim Duncan in the playoffs amounts to a long line of dekes which allow him to draw body contact and go to the foul line. He doesn't deke to score a field goal. He dekes, over and over for however long he is in the playoffs, to draw the body contact. Even a power player such as Moses Malone used to primarily draw body contact and shoot free throws in the playoffs. Unless you are Shaq, Amare, or maybe Dwight Howard, there is no other way to play - yet Nowitski tries to play the other way. It's as if Nowitski considers himself a purist who is above the low down proletariat mud bog pig sty play which goes on in the playoffs. Problem is: pig sty is the game. The defensive athleticism, defensive focus, and playoffs refereeing dictate it. You can't win the pig sty game if you refuse to play it. Dirk is a hardheaded Euro elitist who is blind to reality. Also, he may have a bit of futbol "it's a beautiful game" utopian mindset. Such does not play well against an American "win the damn game" mindset.
Second, Dirk is mentally soft. Comes a moment when a star has to STEP UP AND WIN THE DAMN GAME. Dirk has never been much for stepping up. Today's fourth quarter - especially the first part of the fourth quarter, when the Mavs were down 4-6 points for an extended stretch, and had a chance to win the game - was a clear example: Dirk passed up shots; Dirk passed up opportunities to create shots; Dirk was gutless. Dirk was afraid of failure.
Contrast with another player who briefly played for the Mavs: Nick Van Exel. When it came time to win the game: Van Exel was going to step up and take the damn shot; was going to will the ball into the hole. Van Exel could handle failure; could shoulder responsibility for failing; could say "Yeah, I missed the shot, what of it?" Dirk cannot handle failure. Dirk thinks failure means something other than "I missed the shot, what of it?" Dirk might think failure means something about him; might think it matters that some fool might think less of him for missing a shot. It doesn't matter what a fool thinks. Van Exel knows it doesn't matter. Van Exel might've hated missing the shot, but he didn't hate it because of what some fool might've thought about it.
When Dirk started passing up shots: it threw the Mavs offense out of rhythm, it increased the effectiveness of Denver's defense, and a 4-6 point game became a blowout. It's an odd thing about basketball: when the offense has countered the defense with passes, and ball comes to you and you are open for the shot: if you pass up the shot, it ruins and demoralizes the offense and your teammates. When the shot is properly yours, you have to take it. It's better to miss that shot than to pass it up and destroy your own offense. Dirk passed up shots; he failed to create shots when he had clear opportunity to do so; he destroyed the Mavs offense.