If there is one metal festival you should see this year, it would be the Mayhem Festival. This year's tour officially kicked off Saturday (June 30), and it was a first for many bands on the trek.

It was the first time that acts like Whitechapel and As I Lay Dying were able to debut new music on their current albums. It was a first time for many audience members to catch up-and-coming rock bands like I the Breather or the nattily clad Upon a Burning Body who both generated some attention. But most importantly, it was the first time that U.S. audiences have caught Slipknot since the death of bassist Paul Gray.

That being said, the audience was well aware of the significance of the show as evidenced by the endless sea of cell phones lit up as the opening notes were played and fans anxiously awaited the curtain to drop. Once it did, the band did not disappoint, showing exactly why they're one of the top concert draws in rock. Whether it be the percussive power of Joey Jordison, Shawn Crahan, and Chris Fehn, the showmanship of singer Corey Taylor, the magnified brilliance of guitarist Mick Thomson on a night when Jim Root was not around to aid the guitar attack, or the boundless energy of stagediving DJ Sid Wilson, who also completed several leaps onto the hydraulic 360 drum riser of Crahan. Their performance hit high notes on such favorites as 'Wait and Bleed,' 'Heretic Anthem,' and 'Psychosocial.'

Guitarist Jim Root missed the Mayhem tour kickoff due to an unexpected sidelining. #4 had been ill for weeks leading up to the show before heading to the hospital where he was diagnosed with a burst appendix. Root will likely miss a few more shows before joining Slipknot out on the road but is looking forward to joining his bandmates and fans according to the statement released by the band.

Slipknot had company on the bill by some acts that Chris Fehn told Loudwire they were definitely influenced by. Fehn admitted his admiration for Slayer, and the band put on a powerful and technically awe-inspiring set. With the crucifix setup of the speakers overhead, the band added in a pyro show that was not to be missed with flames emerging from each of the speakers in perfect timing to the beats of lightning quick drummer Dave Lombardo. But the heat onstage was only the beginning as a couple of bonfires generated on the lawn during Slayer's set. Things reached a fevered pitch with circle pits forming all throughout the crowd during the fan favorite track 'Raining Blood.'

The main stage also featured stellar performances from the always-rocking Motorhead and the Devil Wears Prada, who showed exactly why now is the right time for them to be releasing a live album. Meanwhile, Anthrax headlined a second stage where Asking Alexandria stood up to the challenge of winning fans over and As I Lay Dying and Whitechapel powered through performances.

Following Saturday's tour opener in San Bernardino, Calif. the Rockstar Mayhem Festival packed up and headed for Mountain View, Calif. for the second stop Sunday night. The tour is booked through Aug. 5.