Who has the best hard rock hit of the 21st Century? This Rocktober Rumble pairing will help us move closer to finding that out.

System of a Down were all over radio back in the fall of 2001 with their their tongue-twisty single "Chop Suey." The track, from their Toxicity album, also earned the band a Grammy nomination for Best Metal Performance. Take a listen below.

Avenged Sevenfold have seen their star grow with each pending album, and they hit one of their radio highlights in 2010 with the title track from the Nightmare album. The song climbed all the way to No. 2 at rock radio. Rock on in the player provided.

So will it be System of a Down or Avenged Sevenfold? You can vote for which song you feel should be the best hard rock hit of the 21st century once per hour through the deadline of Monday, Oct. 17 at 10AM ET. See more Rocktober Rumble matchups by clicking the red button below.

System of a Down, "Chop Suey"

Avenged Sevenfold, "Nightmare"

Loudwire
Loudwire
Loudwire
Loudwire