'The Voice' Battle Rounds: Christina Aguilera In Tears After Teen Duet (VIDEO)

The Battle Rounds kicked off on "The Voice," and it proved to be very emotional ... for the coaches. While the contestants were paired together and battling for their lives in the competition, the coaches were left to make those sometimes agonizing decision. Christina Aguilera struggled the most when it came time to choose between her teen phenoms, Amber Nicole and Timyra-Joi.

By the time the girls finished their strong performance, Christina had tears in her eyes. "I’ve known this little girl for a little while now and I’ve never seen her cry in a Battle Round competition," Blake Shelton said of Christina.

Perhaps it was one of those moments when the coach regrets pairing two singers together, meaning they can only keep one of them. In the end, Christina went with 17-year-old Amber over her 15-year-old duet partner and rival. In fact, it was their age that Christina used as her deciding factor -- things were otherwise so close between the two.

Hollywood Life's Jordan Clifford felt for Christina, saying that it was definitely a hard choice after that goosebump-inducing performance. Over at Zap2It, Billy Nilles was shocked, but not by Christina's decision. “No one goes in for the steal, which feels absurd," he wrote. "That said, Timyra's youth and her talent combined? She will be a big name in no time.”

Blake admitted that he regretted not stealing Timyra, but it's too late now. She's out of the competition. "The Voice" Battle Rounds continue on Mondays at 8 p.m. ET and Tuesdays at 9 p.m. ET on NBC.

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