Italy had at least 5 great chances before the dismissal, Australia had one and even that might've been after a foul. Therefore I ask, who was the better team before the red card? Whoever says Australia loses all the respect in my eyes because evidently he doesn't know anything about football.
After the red card (which was an idiotic thing for Materazzi to do, although a straight red is questionable) Australia pressured but didn't really create any super scoring chances. Italy couldn't do anything offensice because they tried to defend so tightly and it succeeded, it would've probably gone to penalties without the Grosso foul.
Yes, the Grosso foul was very questionable too. The defender lied there in the ground and it isn't clear wheather he actually used his hands or not. Tough decision for the referee. However, I've seen worst penalties given so that wasn't scandalous, just debatable like the red card.
All in all, Italy played conservatively in the first half but was clearly the better side with more chances. The red card gave Australia a hell of a chance but Italy's defence, particularly Cannavaro was simply gold. Totti shot a nice penalty and that's that. Materazzi almost ruined Italy's chances.
As for what comes to DP, he started well and gave a few good crosses which created good scoring opportunities. He wasn't able to dribble past any defenders though. He had an ok first half and I'm not sure if Totti had done better. In the second half after the red card he couldn't do anything - he's too slow to seriously trouble the whole defense line. All in all he had an ok match, he could've played better but he was definately not atrocious like some have claimed.