Fall Out Boy Swear To 'Avenge' Justin Bieber In Musical March Madness

Fall Out Boy take on the Black Keys in the Sweet 16, and they're repping hard for the Keys' old foe, Justin Bieber.

MTV's Musical March Madness has moved on to the Sweet 16, but for the bands still alive in the tournament, there's no time to rest on their laurels ... because things only get tougher from here on out.

Truly, only the strong have survived, and one look at some of our Sweet 16 matchups only backs up that point: Paramore are going head-to-head with Linkin Park, Fun. battle Green Day, and Ed Sheeran takes on Evanescence, to name just a few. Combine those high-powered matchups with the fact that voting in the Sweet 16 closes Wednesday, April 3 at noon ET ... and you can see why stakes are high, and there's no rest for the weary.

Of course, one of the surviving 16 seems to have no problem with that pace. We're talking about Fall Out Boy, who are definitely making the most of their first MMM appearance: Talking plenty of trash, pasting #12 Of Monsters and Men in round one, and calling out — then subsequently crushing — Chicago rivals Smashing Pumpkins in round two.

Now, they're pitted against the Midwest Region's #1 seed, the Black Keys, with a spot in the Elite 8 on the line. And if you think they're backing down, well, you haven't been paying attention. If anything, they're only elevating the smack talk ... by invoking the name of Keys' drummer Patrick Carney's Twitter sparring-partner: Justin Bieber.

"We must avenge young Bieber and take them down!" FOB bassist Pete Wentz wrote in an email to MTV News, presumably after watching the premiere of "Game of Thrones" on TiVo. "Let's do this."

And right now, it looks like Bieber may be avenged ... Fall Out Boy are currently up big on the Black Keys, though Wentz is smart enough to know that, in MMM, you can never take your foot off the accelerator. So with 24 hours left in Sweet 16 voting, he's making one last effort to point out his band's superiority, and all but punch their ticket to the next round.

"This is an interesting matchup as it would seem neither of us are good at sports — or maybe they secretly are," Wentz wrote. "Good thing it's about who's the loudest ... We are loud, young f---ers."

MTV's Musical March Madness tournament moves to the Sweet 16! Voting is now open in all matchups and polls close Wednesday, April 3 at noon ET, at which point we'll move on to the Elite 8. All winners are determined by your votes, so if your favorite act made the cut, it'll be up to you to guide them to glory! You can spread the word on Twitter using the hashtag #MMM — but get ready, it's gonna be a war.