Guy praised both vocalists saying he was "proud of you both", before giving a lengthy explanation for his decision.
Ultimately, the father-of-two said he was basing his choice on "the person that can benefit the most out of this experience" and deemed that singer to be Jack.
Addressing Chriddy, Guy said: "Just know that this is nothing to do with how you performed buddy - like absolutely nothing.
"You just keep improving. I was looking over to [Boy George] as you were singing and we were both just giving each other the looks of, wow - this dude is serious."
But a dejected Chriddy shocked viewers and judges alike by replying: "Why didn't you pick me?"
Boy George appeared to agree with Chriddy's question, clapping in support along with the studio audience.
"That is the brutality of this show and the brutality of battles," Guy answered awkwardly.
"It's not an easy decision, that's for sure."
Fans of the series were unhappy with Guy's decision, with many taking to social media to air their disappointment.
"This show is rigged! Chriddy had that battle fair and square. So disappointed in your decision Guy. #TheVoiceAU," one person tweeted.
"I literally can't - #TheVoiceAU are we choosing people because of their talent or because of their back stories.. nup bye I actually cannot," another wrote.
Earlier this week, Jack Vidgen revealed he can't stop "bursting into tears" since the start of his stint on the Channel Nine singing show.
Speaking to 9Honey Celebrity, the young vocalist admitted he's been bowled over by the positive public response to his TV comeback, saying he has experienced "so much overwhelming love, kindness and positivity".
The eighth season of The Voice got off to a decidedly shaky start with all four judges getting into a heated argument with a contestant on air, while Delta Goodrem was specifically hit with allegations of cheating after she broke the rules to save one of Guy's acts at the last second.
The Voice Australia continues tonight on Nine at 7.30pm.