Rudd kicked off the battle with Tina Turner's "Better Be Good to Me," and Fallon countered with Foreigner's "Jukebox Hero."
"You're not messing around," Rudd told Fallon after round one.
But then Rudd brought in some pop royalty, rocking out to Queen's "Don't Stop Me Now."
"I concede! I concede!" Fallon said. "The winner right there, Paul Rudd! The champ! Fantastic! Oh my gosh/ … That was off the charts! That's gotta feel good!"