The Scottish singer and harp player was cut by Will in last night's knockout rounds as he chose to take Sophie May Williams, Isher Haughton and Jermain Jackman through to the live shows.
It looks like Will may have made the wrong decision with Anna having notched up over 4 million YouTube views since her first audition, far more than any other competitor, and her Knockout performance is already the second most watched of Sunday's show.
One Anna fan wrote online: "Will made a mistake not taking her through and I bet Ricky wants to strangle him for letting her go home.
"If she'd chosen Ricky's team she would have been through for sure. "
And another put it more succinctly: "What the **** is wrong with Will?"
But others backed the Black Eyed Peas star's decision.
"There was no journey, and I think it was a mistake her using the harp in all three rounds," one viewer wrote on an online forum.
A second added: "The only thing different about Anna was that she played the harp, which I think would have got boring after a while."
Will hasn't been the only judge criticised for his decisions with Kylie Minogue also under pressure after she let Femi Santiago go.
Even Kylie's fellow coaches were surprised with the decision on Saturday night's episode, with Will blaming it on song choices.
"It’s like a hot model with a great physique but with a curtain on," he remarked.
Do you think Will and Kylie made the right choices? Add your thoughts in the comments!
Browse pictures of The Voice 2014 finalists below...