The Team Tom Jones member's version of Whitney Houston's 'Run To You' topped the poll by taking in 25.4% of the vote.
Mitchell beat Danny O'Donoghue's Bo Bruce, whose cover of Coldplay's 'Charlie Brown' saw her come second with 19.9%.
will.i.am's member Tyler James completed the top three, by gathering 13.7% of the vote for his performance of Queen's 'Bohemian Rhapsody'.
The four acts from each team with the least amount of viewer votes will leave the BBC One competition later this evening (May 27).
Digital Spy readers suggest that the contestants that are most in trouble are Jaz Ellington, 5.8% (Team will.i.am), Becky Hill, 7.4% (Team Jessie J), Max Milner, 8.2% (Team Danny) and Ruth Brown, 11.6% (Team Tom).
Vince Kidd narrowly beat his team member Hill with 7.9%.
The Voice UK airs tonight at 7.15pm on BBC One, and will feature a live performance by Kylie Minogue.