The versatile Shanroe shone for trainer Karl Thornton in the Caa Stellar Chester Stakes.
The nine-year-old, who had 10 victories to his credit on the Flat, in bumper company and over hurdles, was last seen winning a Galway contest in early August.
He was the only Irish-trained runner in the Chester Listed event and was a 17-2 shot in a field of five that included St Leger entrant Military Order – the 4-5 favourite.
Shanroe made all of the running from stall one, staying on and holding off every challenger in the home straight to prevail by a length and a quarter under Jason Hart.
Thornton said of the triumph: “He’s always been a classy horse, the conditions seemed to suit him there and Jason gave him a classy ride from the front. He deserved that one.
“He’s tough, it’s not easy getting past him anyway.
“Once we found out we had that draw, we had to use it and there’s no point getting dropped in behind.
“He doesn’t do much in front but when he turned for home, he picked up again and he got the job done.
“His owner (Brian Smyth) passed away, he’d have loved to have been here for this. He’s a horse of a lifetime for folks like us.”
The Group Two Doncaster Cup could be on the agenda for Shanroe at the St Leger meeting, with the Loughbrown Stakes at the Curragh the ultimate aim for the remainder of his Flat season.
“Hopefully he can go on and do a bit more now,” Thornton said.
“The long-term plan is the Group Three at the Curragh on November 5, but he might have an entry in the Group Two at Doncaster in two weeks time, that’d be the plan at the moment.”
Military Order came home last, beaten just under nine lengths, and is now as long as 50-1 with some bookmakers for the St Leger.