Stasys Baranauskas was appealing verdicts that he took part in the sexual assault and inflicted life-changing injuries on another man during the attack in July 2011.
But senior judges ruled his grounds of challenge were “without merit”.
Last year Baranauskas, a Lithuanian national, was found guilty by a jury on eight counts, including aiding and abetting rape, attempted rape, sexual assault and false imprisonment. The 31-year-old was also convicted of causing grievous bodily harm with intent over the incident at a house in Lurgan, and was handed a 15-year jail term.
A second Lithuanian national, 27-year-old Darius Porcikas, received an 18-year prison sentence for the rape and assaults.
Challenging the safety of his conviction in the Court of Appeal, Baranauskas’s defence lawyers argued there were inconsistencies in the woman’s testimony and questioned whether the trial judge should have warned the jury about her evidence.
Further points were raised about identification evidence and the admission of previous convictions.
However, Mr Justice Horner, sitting with Lord Justices Stephens and Treacy, expressed “enormous difficulty” in understanding the basis on which the guilty verdict was being appealed.