Update: Justin Bieber won this round. Click here to vote for his Beliebers in the Semi-Finals!

Okay, guys, brace yourselves. For this year's March Madness, we wanted to do something that would ensure maximum fan energy, and what better way to do that than to find out which of our favorite celebs has the best fanbase? Round one pits One Direction's Directioners against Justin Bieber's Beliebers in what is sure to be a terrifying, metaphorical blood bath. Who has the better fanbase? We're not sure we're ready for the answer.

One Direction have some of the most intense fans to ever grace this planet. From sending enough hate to GQ Magazine over their One Direction cover story to warrant its own post on their site to getting the weirdest One Direction-related hashtags trending on Twitter, there is no shortage of devotion when it comes to defending the guys -- even when they don't need defending. From defacing landmarks blessed by One Direction's presence to being unable to breathe near Harry Styles, Directioners are nothing if not passionate.

Meanwhile, Justin Bieber's Beliebers are notorious for their dedication to the "Baby" singer. From Justin's house eggings to an arrest, the Beliebers have stuck with Justin through it all. We really have to hand it to them for staying strong through Justin's ups and downs, but isn't that what being a fan is all about? Selfless, unbridled devotion and hours spent tweeting your faves? We're pretty sure the answer is yes.

Which fanbase deserves the glory? You can vote once per hour until the polls close at 3PM ET on March 17.

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