Stratum provided Willie Mullins with his second successive victory in the Emirates Cesarewitch at Newmarket.
Ireland's perennial champion National Hunt trainer saddled the first two home in last year's renewal of the £350,000 contest, with Low Sun getting the better of stable companion Uradel in a thrilling finish.
Mullins was again well represented, with the Frankie Dettori-ridden Buildmeupbuttercup and William Buick's mount Great White Shark both prominent in the betting - but it was the outsider of the three Stratum who struck gold at 25/1 in the hands of Jason Watson.
Disappointing when well-fancied for this race a year ago, the Tony Bloom-owned six-year-old has largely failed to fire in valuable handicaps both on the Flat and over hurdles since.
He was a ready winner of a minor event on his most recent Flat start at Killarney, but was turned over as the 1/4 favourite on his latest appearance over hurdles at Listowel.
However, he was back on-song in this fiercely competitive two-and-a-quarter-mile contest, knuckling down in the closing stages to get the better of 50/1 shot Party Playboy - trained by Willie's brother Tony Mullins - by half a length.
"We thought this fellow might do it last year," admitted the winning trainer.
"We brought him back because of the prize-money and he ran well here last year, but he just ran too free. We didn't bring him on the homework he was doing.
"I was disappointed he got beaten the last day over hurdles, but when I looked back at the race the horse still ran a great race. He deserved to come here and I put that race out of my mind and we took our chance in coming and it has paid off.
"It was fantastic to get Jason Watson and he gave him an ice cold ride. Every time I looked at him he was taking a pull, which is a great sign, and he delivered him at the right time."
Mullins insists he would have been just as pleased to see his brother's horse emerge triumphant.
He added: "When I looked at it two furlongs down I thought Tony was going to win the Cesarewitch and I thought 'fantastic for him', and I thought my fellow might run on to be placed.
"It just all changed in a couple of strides. I would have liked Tony to have won it, but what can I say? We have been lucky enough to do it. If we weren't going to win I would have loved Tony to have done it.
"I think he (Stratum) got the position from the start and my other two, when I looked at them after jumping off, I thought 'they have to be super horses to try and get through'. Buildmeupbuttercup flew and Frankie got a great run up the inside, but she just had too much to do from the get-go, and probably the same for Great White Shark."
Mullins is unsure what the future holds for the winner.
He said: "I'm all ears and open to ideas! I was probably going to give him a rest, but we will look at his jumping.
"He has not a break for a while, just mini little breaks, but I don't know we have to do anything with him after that sort of win.
"We came here with the view if he ran bad we would give him a break. We will see how he comes out of the race.
"He has been in training a long time, but when he does what he did today it shows he still has plenty in the tank."