Christina Aguilera has blasted 'The Voice' finalist Tony Lucca for singing '99 Problems'.

The judge has an escalating feud with Tony, and while the rest of the US show's judging panel - Adam Levine, Cee Lo Green and Blake Shelton - enjoyed his bluesy take on the Jay-Z track, Christina took exception to the lyrics, which include the line ''I got 99 problems but a bitch aint one.''

After Tony's acoustic but energetic performance, she told him: ''I thought it sounded great--you have a really cool voice.

''I know your beautiful wife and your daughter and family are here tonight, and I just thought that the lyrical connotation was a little derogatory toward women.''

Adam jumped to his contestant's defence, telling Christina: ''We're not referring to women, we're referring to everything... it's called a metaphor.''

Tony had changed many of the words to the track, altering its context, and also omitted the word bitch from the chorus altogether.

Also competing to win the show are Jermaine Paul, Juliet Simms, Chris Mann.

The winner will be decided entirely by viewer votes, and will conclude with a final episode tonight (08.05.12).