Congrats to Demi Lovato, the newest reigning Pop Clash champ! The singer's 'Nightingale' ousted Austin Mahone's 'Waiting for This Love' by 5%. This week, Demi faces off against Kelly Clarkson's 'Heartbeat Song.'

While we love a Demi power anthem (please refer to 'Really Don't Care), we can't resist listening to her ballads. 'Nightingale' is the kind of vulnerable lullaby that simultaneously shows off Demi's vocals and proves her ability to open herself up to her fans. It also happens to be an incredibly beautiful and powerful song -- making it a fan favorite.

Kelly is charging into 2015 with what's sure to be one of the year's first hits. The singer calls 'Heartbeat Song' "uplifting," and we completely agree. It's brimming with the energy we've come to expect from Kelly, but it still feels very current. Years after her 'Idol' win, she's still bringing it!

Who should win this week's Pop Clash? You can vote for Demi or Kelly once an hour until the polls close at 3PM ET on Jan. 20.

Watch Demi Lovato's 'Nightingale'

Listen to Kelly Clarkson's 'Heartbeat Song'