Katy Perry has won her appeal in a copyright infringement case involving a Christian rapper.

Marcus Gray, who raps under the name of AKA Flame, sued Perry for copyright infringement, claiming that her 2013 No 1 hit "Dark Horse" had taken the beat from his song, "Joyful Noise" featuring Lecrae, without his permission. 

"Defendants never sought or obtained permission from plaintiffs to use the 'Joyful Noise' song in creating, reproducing, recording, distributing, selling, or publicly performing defendants' song," Gray and his team claimed. 

"Plaintiffs never gave any of the defendants permission, consent, or a license to use 'Joyful Noise' for any purpose, including creation of a derivative work based on 'Joyful Noise'."

During the trial last July, Perry claimed she had never heard of the song or Gray before, and her lawyers argued that Gray was unfairly "trying to own basic building blocks of music, the alphabet of music that should be available to everyone". 

Giving evidence in court, musicologist Todd Decker disagreed, saying that there were "five or six points of similarity" between the two songs, including pitch, rhythm, texture, pattern of repetition, melodic shape and timbre.

The jury sided with Gray and ordered Perry and other members of her production team to pay $2.8m in damages. 

Of this total, Perry was to pay $500,000. Rapper Juicy J, who appeared on the track, and producer Max Martin were also ordered to pay a share of the damages. 

But judge Christina Snyder has now overturned the jury's verdict after Perry appealed. 

Delivering her verdict, Snyder said it was "undisputed" that the beat in Dark Horse was "not a particularly unique or rare combination", the Guardian reports. 

The newspaper reports that Gray intends to appeal the appeal decision.