"The Voice": Competition stiff as top 6 perform

From left, Adam Levine, Cee Lo Green, Christina Aguilera, Blake Shelton, Carson Daly of "The Voice."

It's down to the nitty-gritty on NBC's "The Voice." With just six contenders left, competition is stiff, as more mentors will soon have to say goodbye to their artists. Each of the finalists performed two songs  on Monday night for the coaches.

Cee Lo Green was sick this past week, so he sat out during rehearsals. Train singer Pat Monahan stepped in to mentor Green's remaining two contestants. Green helped coach contenders over the phone and was on board for the live performance round on Monday.

Christina Aguilera, who doesn't have anyone left in the battle, was there to chime in on the artists' performances.

Here's how it all went down.

Team Cee Lo

Nicholas David first tackled Earth Wind & Fire's "September," a song selection made by Green. He chose his second selection, "Somewhere Over the Rainbow," because it's his mother's favorite song - and it ended up being a hit. "I love what you do every time," Adam Levine told David. Mentor Blake Shelton described David's rendition of the classic as "magic and beautiful."

Buzzed-about contender Trevin Hunte blew away the judges again this week. The 18-year-old singer first sang "Walking on Sunshine" by Katrina and the Waves.

Green said, "It made me feel so much better to see you happy and moving."

For his next song, Hunte sang Jennifer Hudson's "And I Am Telling You I'm Not Going" from the "Dreamgirls" film and Broadway show. He received a standing ovation.

"I hope Jennifer [Hudson] never hears that because she will quit the business," Monahan said.

"That's one of the best performances I've seen on the show, maybe ever," Levine noted, and Aguilera told Hunte, "I'm recovering" from what she thought was a fantastic performance. Green, clearly impressed with his team member, joked that he wanted to take a moment to "mourn the loss of all the other competition."

Team Blake

Cassadee sang Rascal Flatts' "Stand," a song chosen by mentor Blake Shelton, who later told the contender, "You made it your own and it was amazing." Levine liked it, too, but said he was hoping Cassadee would do something "different."

For her second song, Cassadee belted out Avril Lavigne's "I'm With You," a smart choice, as all the mentors were pleased.

Green told her, "You never cease to amaze me," and Shelton said that performance could win her the competition. Levine said it was her best performance yet.

Scottish rocker Terry McDermott sang Foreigner's "I Want to Know What Love Is," which brought Shelton and Aguilera to their feet.

Green told McDermott, "You're really amazing...I love your rendition." Adam noted, "You always blow us away," and Shelton added, "That was unbelievable!"

More praise came for McDermott with his second song: Rod Stewart's "Stay With Me." Levine called McDermott an "incredible singer."

Team Adam

Melanie Martinez tackled Cee Lo Green's "Crazy" and Lenka's "The Show." Aguilera thought Martinez should take on a more sultry number, while Green said, "You did a great job." Shelton told Martinez, "That was definitely different," before complimenting her singing skills.

Amanda Brown performed "(You Make Me Feel Like) A Natural Woman" by Aretha Franklin and Whitesnake's "Here I Go Again."

Shelton said, "You're a world-class singer." Aguilera, too, was a fan, saying Brown did a great job.

Despite all of the praise, not everyone can stay in the competition. "The Voice" returns tonight at 8 p.m. ET with a new live results show. The remaining six singers will learn their fate as votes are announced. Matchbox 20 and Ne-Yo will perform.

Tell us: Who do you think will win "The Voice"?

Watch Trevin Hunte at rehearsals: