It's only the first round of March Metal Madness to determine the Best Metal Song of the 21st Century, but the matchups are intense right from the start. Nothing will be easy here as the ringleader of musical horror Rob Zombie and "Feel So Numb" look to defeat metalcore pioneers Killswitch Engage and their hit "My Last Serenade."

Like an industrial strength James Brown, Rob Zombie doesn't just "feel good" he feels so good! "Feel So Numb" comes off Zombie's second solo album, The Sinister Urge, and was one of the definitive anthems of the early 2000s. The danceable rhythm crossed over with a multitude of heavy music fans, expanding his fanbase and helping Zombie net a Platinum album in the process.

Right before metalcore really took off, Killswitch Engage were leading the pack with Jesse Leach barking his way through melody infused rhythms and soaring clean vocals over lush choruses. "My Last Serenade" showcased the band's rage forged with beauty as the band was poised to explode over the ensuing years. They've got a tough opponent in Round 1, but so does Rob Zombie!

So which song will move on to the second round of March Metal Madness 2016? Listen to both tracks and vote for either Rob Zombie's "Feel So Numb" or Killswitch Engage's "My Last Serenade" as the Best Metal Song of the 21st Century in the poll below!

(This poll will end on Tuesday, March 8, at 9AM ET. Fans are able to vote once per hour, so keep coming back to make sure your favorite song wins!)

Rob Zombie, "Feel So Numb"

Killswitch Engage, "My Last Serenade"