Those artists were Kirk Jay, a 22-year-old from Bay Minette, AL; MaKenzie Thomas, a 20-year-old from Wallingford, KY.; Chris Kroeze, a 27-year-old from Barron, WI; and Chevel Shepherd, a 16-year-old from Farmington, NM.
Each artist performed twice on Monday night's The Voice broadcast -- a new song as well as a duet with another contestant -- in the hope of landing a spot in next week's finale.
MaKenzie, who represents "Team Jennifer," sang "Vision of Love" by Mariah Carey.
"I cannot stand you; you are so good!... That was bold, that's Mariah! MaKenzie, you are so good. This show is called The Voice and that's what this show is all about," Kelly explained.
Blake said it was "one of the best performances" he's ever seen and he admired how she "worked the microphone."
Jennifer urged America to vote for MaKenzie because she's "amazing" and deserves to be in the finals. Jennifer added she's "a coach's dream" but she also adds her own expertise and specialty to a song.
"She's amazing on her own -- coach or no coach," Jennifer insisted.
Chris, a member of Blake's team, belted out "Can't You See" by Marshall Tucker Band.
Kelly called Chris "a storyteller" and noted his voice is "so nostalgic," like going back to Guns N' Roses. Blake said he "did awesome" and he gave "beer drinking" and "back-road driving" viewers of the show someone to root for.
Chevel, a proud member of "Team Kelly," performed "Blue" LeAnn Rimes.
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Adam said he loves her voice, the music she plays and what she represents on the show. Kelly said she missed this pure country sound and really wants Chevel to make a record.
Kirk, who sings on behalf of Blake's team, took the stage with "I Swear" John Michael Montgomery.
Jennifer said Kirk blows Jennifer away every single time with his voice, and Adam pointed out he has a very unique and distinct sound that's important to music.
"I don't want to say anything funny or witty. I just want to say that, as your coach, I could not be more proud of you and you deserve this, man," Blake told his team member.
The other contestants in this season's Top 8 also delivered excellent and memorable performances.
"Team Kelly" member Sarah Grace, a 15-year-old from Houston, TX, sang "Sign of the Times" by Harry Styles.
Jennifer said she wasn't sure if she's more of a fan of her "bravery" or "talent." Jennifer said her confidence showed and she "commanded the entire room" from start to finish.
Kelly complimented Sarah's ability to play the piano as well as the "soft and sweet" subtleties and dynamics in her voice that make her so special.
Fellow "Team Kelly" member Kymberli Joye, a 26-year-old from Windsor, CT, belted out "Never Alone" by Tori Kelly featuring Kirk Franklin.
Jennifer said she opened the doors to a church and she felt like she was at a gospel, musical concert.
Kelly gushed about how much she loved Kymberli. Kelly said "very few people on the show can sing like that" and she's watched many seasons. Kelly said Kymberli sings from the heart and she "better make the Top 4."
"Team Jennifer" member Kennedy Holmes, a 13-year-old from St. Louis, MO, performed "This Is Me" from The Greatest Showman.
Jennifer said she's so proud of Kennedy and how much she's grown. Jennifer added she proved that it's okay to be exactly who you are and it was clear the song meant a lot to her.
And the last person standing on "Team Adam," Reagan Strange, a 13-year-old from Memphis, TN, sang "You Are the Reason" by Calum Scott.
Blake said she loved the performance and it was "a breath of fresh air" because it was laid back and moody. And Adam explained he's so happy for her because she demanded the audience to be quiet so she could deliver her most raw and pure vocal to date.
Adam insisted Reagan deserves to be in the finale, but regardless of what happens, she has a very bright future ahead of her.
For the duets, Reagan and Kennedy Holmes sang "Happy/Tightrope" together, Kirk and Chevel took the stage with "She's Country/Country Must Be Country Wide," Kymberli and MaKenzie belted out "Got to Be Real/Best of My Love," and Chris and Sarah Grace performed "Jumpin' Jack Flash/Chain of Fools" together.