Linkin Park, Paramore Battle for Survival In Musical March Madness

30 Seconds to Mars, Tokio Hotel, Panic! at the Disco also locked in tight matchups in the final hours of the Sweet 16.

When MTV's Musical March Madness tournament moved on to the Sweet 16 on Monday, we warned that the challenge for bands and their fans would only get tougher from here on out. And we weren't kidding.

Check out our MMM Bracket right here!

With Sweet 16 voting set to close Tuesday at midnight ET, half of our matchups are still too close to call, as big-name artists slog it out for a spot in the Elite 8. Will this be the round where presumptive favorites fall? Will we see upsets of VCU-like proportions? Well, all of that's up to you, really. There's still time to cast your votes and help your favorite bands advance ... but that time is quickly dwindling.

Sweet 16 voting is now under way over on the Newsroom blog!

And sure, some of our Sweet 16 matchups are basically foregone conclusions — #3 My Chemical Romance lead #2 Radiohead by a large margin, #16 Sum 41 are rolling #4 the Strokes, #9 Disturbed are dominating #12 Patrick Stump and #3 Green Day are running away from #2 Blink-182 — but we've got a whole lot of nail-biters brewing ... so here's a look at those ultra-tight contests.

#1 30 Seconds to Mars v. #5 Panic! at the Disco

When we revealed our Sweet 16, we had this West region clash circled, writing "there may be no bigger matchup in the tournament to date." And so far, it has lived up to the hype. Both bands have been campaigning hard, and their fans have responded, casting nearly 70,000 votes at press time. This one looks like it's gonna come down to the wire, as 30 STM lead Panic! by less than 2,000 votes. You can help decide the winner by voting now.

#1 Linkin Park v. #5 Paramore

A huge matchup in the South region, this one pits two MMM title faves against each other ... and the results speak for themselves. More than 80,000 votes have been cast so far, and with just hours left until polls close, fewer than 200 votes separate the two bands. Both Mike Shinoda and Hayley Williams have been hitting up the fans for support, and right now, this one is LP's to lose ... but anything can happen. You can vote for your favorite here.

#6 Coheed and Cambria v. #7 Avenged Sevenfold

All eyes are on this tilt in the Midwest region, as Coheed — last year's MMM champs and the band most had penciled in for the 2011 finals — are standing on the brink of elimination. With hours left to go in the polling, and more than 40,000 ballots cast, they trail Avenged Sevenfold by less than 2,000 votes. If they want to keep their dreams of a repeat alive, they're going to need some help from their fans. Or perhaps this really is A7X's time. You can decide this ultra-close contest by voting now.

#14 Tokio Hotel v. #2 Muse

Another tight one in the South — what else would you expect from two bands that made the Final Four last year? — with nearly 60,000 votes already counted, it's Tokio Hotel who hold a 3,000 vote lead over Muse. It's unquestionably both acts' toughest tournament challenge to date. Could this be the round where Tokio Hotel's fan support finally runs out? Or will it be Muse who fail to live up to the pre-tourney expectations? Once again, it'll be up to you. Vote now to send your favorite on to the Elite 8.

MTV's Musical March Madness has reached the Sweet 16! Voting is now open and will continue until Tuesday at midnight, when we'll roll on to the Elite 8. All winners are determined by your votes, so, if your favorite act is still standing, it's up to you to guide them to glory. You can rally the troops on Twitter using the hashtag #MMM — but get ready, things only get tougher from here on out!