MIAMI (AP) - Each of the diamonds in Shaquille O'Neal's three championship rings are authentic.

These days, he feels like a fake.

Now five weeks into his battle with a bruised right thigh, O'Neal's confidence and productivity are well off their usual playoff levels. And no one, not even O'Neal himself, knows what he'll be able to do when the Heat open the Eastern Conference finals Monday night in Miami against the defending NBA champion Detroit Pistons.

''I'm used to being the good-looking Shaq. Anything that doesn't look good is not worth looking at,'' O'Neal said Sunday after sitting out practice to rest his leg. ''Right now, I'm a high-class diamond that's getting mistaken for a cubic zirconium.''

The Heat hope some of Shaq's mega-carat luster begins getting restored in Game 1 against the Pistons, who are in the East finals for the eighth time since 1987.

It's just the second trip to this playoff round for Miami, which was ousted in five games by Michael Jordan's Chicago Bulls in 1997.

Detroit has a champion's swagger and confidence.

But Heat center Alonzo Mourning, the only holdover from the '97 squad and the presumable replacement if O'Neal struggles, says his team should also feel good about its chances.

''They're a good team. They're the defending champions. But they can be beat,'' Mourning said. ''They've shown their vulnerabilities. They're not invincible. They're not the Chicago Bulls. They can be beat. We can be beat if we don't come right. We're going to be ready and they better be ready.''

The Pistons didn't fear O'Neal when they faced his Los Angeles Lakers in last year's NBA Finals. Detroit used 1-on-1 coverage against him last season, almost conceding the three-time Finals MVP huge numbers - he averaged 26.6 points and 10.8 rebounds while shooting 63 percent in the Lakers' five-game loss.

No one is quite certain what scheme Pistons coach Larry Brown will employ most against O'Neal in this series.