Celtics really seem to favor this series much much more than they did with Cleveland. As good as a defensive team the Pistons are, they have a very weak interior defense. And the Celtics exploited on that weakness right from the get-go. Now that they don't have to worry about double-teaming or triple-teaming a superstar, and getting to the penalty early every quarter, they're able to play good man-to-man and help defense.
If Pistons want to win, they have start doubling Pierce, and try to play zone defense to compensate for their lack of an intimidating interior defense.

Billups 9 points, 2 rebounds, 2 assists, 2 steals, 2 TO
Rondo 11 points, 2 rebounds, 7 assists, 5 steals, 1 TO
When the Pistons' best matchup is getting owned by his counterpart, you know the Pistons are in for a tough night.

Pistons' key to winning game 2:
[1] Play zone defense
[2] Double Pierce, or demand more from Prince's defense
[3] Billups getting into a groove early
[4] Rasheed should avoid being tentative in guarding Garnett

IMO Game 2 is a must-win for the Pistons, else the Celtics' confidence would sky rocket.