For the second week in a row, 5 Seconds of Summer conquered the Pop Clash competition. The band faced off against Austin Mahone and ultimately took 56 percent of the votes. Now they're facing superstar Lady Gaga's 'G.U.Y.' Who should win this week's Pop Clash?

5 Seconds of Summer burst into our hearts with the bombastic 'She Looks So Perfect.' The guys' upbeat love track makes us want to run away with them. (Seriously, they can't sing about buying a lady a plane ticket and not make us swoon!) Never has American Apparel underwear sounded so utterly romantic.

Provocateur Lady Gaga is all about being assertive, and she's at her most straightforward in 'G.U.Y.' (After all, the acronym does stand for "girl under you.") The track features signature Gaga elements: catchy beats, chant-heavy hooks and the singer's fearless confidence.

Who should win this week's Pop Clash? Vote for 5 Seconds of Summer or Lady Gaga until the poll ends on April 7 at 3PM ET.

Watch 5 Seconds of Summer, 'She Looks So Perfect'

Watch Lady Gaga, 'G.U.Y.'