Hot 100 March Madness 2013: Vote Now in Round 2!

Cast your ballot for the best Top 5 single of the past year.

Taylor Swift and fun. moved on, both Justins fell early, and Rihanna went two-for-three: Round 1 of Billboard.com's Hot 100 March Madness has come to a close, with 16 Top 5 hits from the past year soldiering on from the original field of 32. With the first round of match-ups finished and over 70,000 votes already cast, it's time for another round of voting to determine which eight songs continue toward 2013 March Madness glory.

To help determine the winner of Hot 100 March Madness 2013, check out the updated bracket of songs, and vote for your favorite tracks in the head-to-head match-ups below!

ROUNDTWO

From April 1, 2012 through the charts dated March 9, 2013, there have been exactly 32 songs that appeared in the Top 5 of the Hot 100 chart. The match-ups within this year's Hot 100 March Madness bracket were decided arbitrarily, with those 32 hit singles placed in random competition in a quest to follow last year's winner, Britney Spears' "Hold It Against Me." Click here to see the original bracket.

On Friday (Mar. 15), we'll reveal the eight songs that won their second-round match-up, and another round of voting begins. On Thursday, Mar. 28, a new Hot 100 March Madness champion -- the Top 5 song that you think was the hottest single of the past year -- will be crowned.

Looking back at the first round of action, the pop divas prevailed at the expense of the male phenoms: while One Direction, Justin Bieber, Bruno Mars and Justin Timberlake all watched their hit singles fall in the first round, Taylor Swift was trouble the moment she walked into the round, while Nicki Minaj let her "Starships" fly and Katy Perry was "Wide Awake" with a win. The closest battle was between Swift's "We Are Never Ever Getting Back Together" and Rihanna's "Stay" -- Taylor's break-up anthem topped the "Unapologetic" track by a mere 300 votes. But never fear, Navy members: Rih's "Where Have You Been" and "Diamonds" won their individual match-ups against and 1D's "Live While We're Young" and the Lumineers' "Ho Hey," respectively. And give some props to fun.: the best new artist Grammy winners pushed both of their March Madness songs, "We Are Young" and "Some Nights," into Round 2.

Meanwhile, One Direction's other competitor, "What Makes You Beautiful," was absolutely crushed by Will.i.am & Britney Spears' "Scream & Shout": the collaboration earned 82 percent of the vote in the match-up, sending the boy band home early. Next up for "Scream & Shout" is a tough battle with Maroon 5's long-running No. 1 hit "One More Night," which easily topped Justin Bieber and Nicki Minaj's "Beauty and a Beat." Can Britney continue her Hot 100 March Madness title defense? Only time will tell.

Vote now for your favorite tracks below, and be sure to discuss the bracket in the comments section!