Alex & Sierra have yet another win under their belts! After four consecutive Pop Clash championships, the 'X Factor' winners' single 'Scarecrow' is officially being retired to the Hall of Fame.

In the first round, the duo kicked off their winning streak by beating out 5 Seconds of Summer's 'Amnesia' with nearly 62% of the vote!

Next, Alex & Sierra upped their game by taking on Jacob Latimore's 'Heartbreak Heard Around the World' -- and scoring 73% of the votes.

In their third matchup, Alex & Sierra faced off against Nick Jonas' edgy new single, 'Chains.' Although Nick's fans put up a good fight, 'Scarecrow' still managed to score 53% of the votes.

Last week, Alex & Sierra met their strongest competition yet: Jessie J's 'Bang Bang,' featuring Ariana Grande and Nicki Minaj. The power of three divas wasn't enough to oust the duo, who earned 71% of the votes -- and the Pop Clash victory!

They're officially unstoppable. Congrats, Alex & Sierra!

Watch Alex & Sierra's 'Scarecrow' Video