The panel, which also includes Tamzin Outhwaite, Duncan James and Anastacia, opted to hand Swish the last remaining spot in the final on last night's live show.
Speaking about his decision on Twitter, the US choreographer said: "Swish had an extra element about them that reached right through the screen and into your soul. Their passion and commitment was undeniable.
"They gave us both a ballad and a rock song, both a mature theatre performance at the beginning and some youth towards the end... It was the most well rounded of the bunch. I will stand by that decision no matter how much I love both MT4uth and Dice."
He added: "Tonight, it came down to exactly this. I felt a wall between me and Dice. I felt Swish break that wall down and I believed their energy and passion. It's not always about the perfect technique or mechanics. It's about pure entertainment at the end of the day. I think Swish has that secret ingredient and I'm hoping the Dice fans of the world won't hate because Dice will be just fine on their own. I believe in them at the end of the day too."
The Don't Stop Believing final airs on Sunday at 5.30pm on Five.