UPDATE: Kelly Clarkson's 'Since U Been Gone' won in Round 1! Vote for 'Since U Been Gone' in Round 2 of the competition here.

Welcome to March Music Madness! Here at PopCrush, we've selected 32 of the most iconic pop songs released from the '80s to today (divided into brackets by decade) -- and now it's your job to vote and decide which song will be named the Greatest Pop Song of the Modern Era. May the best song win!

Taylor Swift and Kelly Clarkson are both down-to-earth, charming and super talented! The ladies are known for their ultra-catchy pop songs and their ability to connect with fans. Taylor and Kelly have collectively released a ton of pop hits, including 'You Belong With Me' and 'Since U Been Gone.' Which pop song is more worthy of being named the Greatest Pop Song of the Modern Era?

Taylor's first pop crossover hit, 'You Belong With Me,' established her as the slightly dorky girl next door. In the track, T.Swift confesses to preferring T-shirts over miniskirts and always feeling like she's sitting on the sidelines. Awww! The upbeat song, which was nominated for three Grammys and became one of her best-selling singles, proved to be a major pop hit that is still in high rotation today.

Kelly's first single from her sophomore album was 'Since U Been Gone.' Although she'd already released numerous post-'American Idol' tracks, the powerhouse song proved to be an instant classic. The chorus allows Kelly to show off her amazing vocals, while the lyrics empower the listener. To this date, it's one of the 'Idol' winner's most successful hits -- and it even won her a Grammy Award in 2006.

Which song is more iconic: 'You Belong With Me' or 'Since U Been Gone'? You can vote once an hour until March 11 at 12PM ET, when the polls for this round close. The song with the most votes will move on to Round 2 and become one step closer to being named the Greatest Pop Song of the Modern Era.