The Who's classic hit 'Baba O'Riley' was front and center on Tuesday night's episode of NBC's singing competition 'The Voice.' The song served as the basis of a battle between two contestants on pop star Christina Aguilera's team.

Aguilera, who is a coach on the show, pitted soulful singer Justin Grennan against rocker Beverly McClellan in a battle that would feature the two contestants singing 'Baba O'Riley' in a boxing ring. When Aguilera told them what song they were singing, she seemed to pronounce the tune as 'Bubba O'Riley.'

Grennan appeared equally perplexed over the song, admitting he didn't really know it. "I've never seen the lyrics until today," said Grennan. "It's very challenging for me to learn the song." Perhaps, he should have checked out this site's list of the Top 10 Album-Opening Tracks.

McClellan, on the other hand, was psyched to learn that she'd be performing the Who anthem for the battle. "I love the Who, man," she exclaimed. "I'm gonna do [the song] some justice."

When it came to the singing battle, the two traded verses on the song. Grennan did an admirable job performing the tune, but McClellan's powerful voice seemed to overwhelm him. In the end, Aguilera decided to choose McClellan to move on to the show's next round.

Watch Beverly McClellan and Justin Grennan Performing 'Baba O'Riley' on 'The Voice'