SAN JOSE, Calif.--Rock legends on the nostalgia tour circuit should be careful who they choose as opening acts.

Up-and-comers without a deep catalog are fine, as are fellow aging vets looking to tap the Heavy Metal Parking Lot demographic.

But if you're Heaven and Hell--Black Sabbath's Tony Iommi and Terry "Geezer" Butler reunited with their one-time frontman Ronnie James Dio--picking Megadeth might not be your best move. Heaven and Hell performed a solid set last night at the HP Pavilion here, thrilling fans of early-'80s Sabbath with its dredging rhythms, dark imagery, and Dio's theatrical vocals.

The problem was that the music they played, albeit adept and raucous, simply couldn't top the explosiveness that Megadeth brought to the stage in its 50-minute opening set. Frankly, Dave Mustaine and company blew the doors off the place.

Backed by brothers Glen and Shawn Drover on guitar and drums and bassist James Lomenzo, Mustaine led the quartet through a blistering set that took off from the moment they hit the stage.

Leading with "Sleepwalker" from the band's forthcoming new album, United Abominations, they rattled through four songs and nearly 20 minutes of thrash metal without taking a break. When they finally did, it was brief, and they stormed back into "Hangar 18" from 2004's Rust in Peace.

It was a scorching set that felt alive and current, particularly on "Washington Is Next," the band's next single. The track revealed Mustaine's unique perspective on current events, given his Christian faith and devout antiwar stance: "Attack the church dynamic, attack the family/Keep the public undisciplined till nothing left is sacred and/the have-nots get hooked and have to go to the haves just to cop a fix."

By the time it was over, the crowd, slow to arrive because of extensive security checks for those on the floor of the arena, was foaming at the mouth with excitement.

Backed by a set of stone pillars and arches, wrought-iron fences, and video screens, Heaven and Hell took the stage to thunderous applause and dove right into the dark dirge of "After All (The Dead)," taken from the group's 1992 reunion album, Dehumanizer. The song was a bit of a crawler, with Iommi and Butler taking a backseat, as they did for most of the night, to Dio's over-the-top vocals. It was a bit of a slow start, but it showed that Dio's voice has aged well because it seemed as strong and as ever.

The title track from Mob Rules was up next, followed by "Children of the Sea" from 1980's Heaven and Hell--regarded as the group's best album together--hence the choice of moniker for the reunion.

Iommi stuck to droning guitar parts while Butler and drummer Vinny Appice laid down an ominous rhythmic backdrop. All three allowed Dio plenty of room to do his thing, preening around the stage, flashing devil horns, and belting out lyrics that were both descriptive and menacing. But at 64, the elfish Dio isn't very scary, and the music wasn't either. The excitement was there at times, but it only came in spurts on this night.

The obvious highlight was "Heaven and Hell," the most hook-laden song of the night and the one that seemed to give the room a booster shot. Dio, basked in a haunting red light, screamed, "I want to burn in hell with you and you and you" as he pointed around the crowd. It was pure, unadulterated 80s metal at its finest.

But it just didn't quite match the surge that Megadeth had sent through the crowd two hours earlier.

To be fair, it's tough to compare an '80s revival band to one that is led by a fellow vet who seems genuinely rejuvenated. Heaven and Hell are mining music from a specific era, while Megadeth's new album seemed fresh and charged last night. But if they're on the same bill, there's no way to avoid it.