Litigant won the Betfred Ebor at York on his first run for trainer Joe Tuite in the hands of Oisin Murphy.
Not seen for 491 days, the seven-year-old gave Murphy a scare at the stalls before the off but there were no problems in the historic handicap itself.
As Aidan O'Brien's Fields Of Athenry moved up to dispute matters with John Reel, the field appeared to go a strong gallop and the former led the runners into the straight.
Kicking again three furlongs from home, it momentarily looked like young Donnacha O’Brien might record a famous success, but his run began to falter as Litigant came to the fore.
Running on strongly, the 33-1 winner had a length and a half in hand of Wicklow Brave, with Suegioo another neck away in third and Toe The Line fourth.
Murphy said: “I take my hat off to Joe Tuite, because I worked this horse a few times and he wouldn’t work to 60.
“But Joe said keep the faith, with a bit of ease in the ground he’s a different horse — I must say he’s bolted up today.
"They went a good gallop, but he's got enough class. In fairness to George Baker, he told me this is a Group horse, obviously having had so few runs and been off for so long it's hard to see it but he was proved right."
Tuite said: “I wanted to give Oisin a winner this season. I said I was sorry and I hoped it would be this horse.
“That was superb. I’m speechless. It’s a marvellous team performance — I’ve got the best team in racing. I’ve got 20 horses in training and six members of staff. We wanted rain. It didn’t come, but it’s perfect ground.
“They’ve worked unbelievably hard to get this horse back to the track. He’s very delicate.
“We’ve had a few quid on and we’ve dreamed it. We know he’s very good when he comes right.
“He’s a very good horse and has only been beaten twice in his career.
“I’m a lucky man that Tony (Byrne) sent this horse to me.
“We’ve got to look at the two-miler on Champions Day at Ascot now.”
Willie Mullins said: “I was a bit disappointed with Clondaw Warrior. He’s had a lot of racing and maybe it’s taken its toll.
“But Wicklow Brave ran a cracker. I don’t know what we’ll do next.
“We’ll go home and think about it.”