Conor McGregor (left) attacks Max Holloway with a kick at the start of a welterweight fight during UFC 329 in Las Vegas on Saturday. AP-Yonhap Conor McGregor's long-awaited return to the Octagon ended in disappointment Saturday after the Irish star suffered a knee injury just 1:09 into the opening round of his welterweight main event against Max Holloway at UFC 329 in Las Vegas.Making his first UFC appearance in more than five years, McGregor received a thunderous ovation from a sellout crowd. But the highly anticipated comeback was over almost as soon as it began.Moments after the opening bell, McGregor launched a flying left roundhouse kick but landed awkwardly on his right knee. Although he attempted to continue and threw two more strikes at Holloway, the referee stopped the fight after it became clear he could not continue.UFC President Dana White said doctors believe McGregor may have suffered a torn anterior cruciate ligament.The rest of the main card delivered plenty of action.In the lightweight division, Liverpool's Paddy Pimblett stopped Benoit Saint Denis by first-round TKO just 52 seconds into the fight after blocking a round kick, shooting in and securing a front headlock.In a bantamweight bout, Mario Bautista earned a unanimous decision over Cory Sandhagen after taking control with leg kicks and sustained pressure throughout the fight.Brandon Royval submitted Lone'er Kavanagh with a rear-naked choke at the 3:40 mark of the third round in their flyweight bout.The night's most dramatic finish came in the opening fight of the main card, where a bloodied King Green rallied from a one-sided first round to stop Terrance McKinney by TKO at the 4:59 mark after landing a crushing right hand with about 20 seconds remaining.(This article was produced with the assistance of AI. — Ed.)