It was a battle of the titans on late-night television as first lady Michelle Obama and "Late Night" host Jimmy Fallon faced off in a White House exercise challenge.

First came the stair race, then pushups and hula-hooping . A tug of war in the Diplomatic Reception Room soon followed, along with a punishing round of dodge ball. In the big finale, the first lady beat Fallon in a potato-sack race across the East Room (cue the slow motion and victory soundtrack).

Obama's appearance Tuesday on NBC's "Late Night" was part of her ongoing promotional tour to mark the second anniversary of her "Let's Move!" initiative to fight childhood obesity.

"The most important thing for the kids to learn is that it's all about being active and having fun and it doesn't matter if you won or if you lost," a breathless Fallon said after his defeat.

"Oh, it matters," Obama said.