In one of our closest Pop Clash races ever, Demi Lovato ousted Heffron Drive to move on to the next face-off! The 'Really Don't Care' singer claimed 50.31% of the votes -- talk about tough competition! This week, she's challenged by 5 Seconds of Summer's 'Don't Stop.' Which song should win the Pop Clash?

Demi Lovato radiates self-confidence in 'Really Don't Care.' The anthem, which describes how the singer refuses to let someone mess with her head, is super empowering for her Lovatics! Not only is the track super catchy, it has a feel-good message. Is this the perfect Demi song? We think so! (Just be warned that the lyric vid is a little NSFW!)

Speaking of feel-good, 5 Seconds of Summer are totally making us swoon with their new song, 'Don't Stop.' The track packs all of the power of 'She Looks So Perfect,' but has a breezy, summery tone to it. It's upbeat, rocking and we found ourselves singing along on the first listen.

Who should win this week's Pop Clash? You can vote once an hour until the polls close at 3PM ET on June 2.

Listen to Demi Lovato, 'Really Don't Care'

Watch 5 Seconds of Summer, 'Don't Stop'