Stradivarius squeezed through the smallest of gaps on the home turn for a dramatic fifth win from five starts this year in the £530,000 G2 Qipco British Champions Stakes.
Trainer John Gosden admitted afterwards that the participation of a colt he described as "fabulous" had been "touch and go" owing to unsuitably soft ground.
After the four-year-old, who was third last year, had scored by a length and a half under Frankie Dettori from one-time Gosden inmate Thomas Hobson and then survive a stewards' enquiry, having drifted right and checked the runner-up inside the final furlong, the trainer said: "I said on Racing UK beforehand that the ground was one thing, but we are going to get put in the box from stall one and he'll have to be Houdini to get out of it - well he did.
"He saw that glimpse on the bend and he dived for it. Ryan (Moore, on Flag Of Honour) tried to shut it but he was too late. It was a very clever ride. If he'd tried to come round, he would have been put back in that box.
"He's a great horse - a fabulous horse - who didn't like that ground, but what a clever ride to take that one opportunity. We committed sooner than we wanted to on ground he didn't like, but it was jockeyship at its highest level.
"He benefited from the break (since his last race). I wouldn't have come here unless he was in great order. Bjorn (Nielsen, owner/breeder) and I had a long talk out on the pavement for 15 minutes after I walked the course and it was touch and go whether we ran him, but I said ''It's Champions Day and we should run.
"The ground is in pristine condition, although yes it's too slow for him. They won't go a great gallop and our problem will be getting out of the box, so full marks to the horse and the jockey for being brave enough to go through that tiny little gap. Lucky he's not a big horse, isn't it."
Stradivarius, the champion stayer, stays in training and will bid to repeat this year's success in the inaugural Weatherbys Hamilton Stayers' Million. He is already only 9/4 from 52 with Ladbrokes for its centerpiece, the Gold Cup at Royal Ascot in June.
Gosden said: "He won't run until May, when he will reappear in the Sagaro Stakes here at Ascot or the Yorkshire Cup, and then we will try to win the Weatherbys Hamilton Million once again."
Frankie Dettori steered the evens favourite Stradivarius to victory but it was a hard-fought success.
The John Gosden-trained four-year-old, who has won all four of his previous starts this season including the Gold Cup at Royal Ascot, burst into the lead on the far rail after turning into the finishing straight, but had to hold off Thomas Hobson to win the £530,000 Group Two race by a length and a half.
"Obviously Ryan [Moore, riding Flag Of Honour, who made much of the running] was the one to beat. I had to shield Stradivarius a bit and then I was in the lap of the gods trying to get a run," explained Dettori. "When his horse didn't turn [into the straight] very well, I thought, I know I am committed - I might not get another chance. I got out of that pocket. For him [Stradivarius] I went far too soon, but I had to take the commitment. In fairness, he answered every call, and I wouldn't have done it if I didn't have that much horse. I had so much horse that I was able to take the gap in a split second before even Ryan realised.
"Stradivarius has been a model of consistency and he deserved to be crowned champion stayer. What a season it has been for him."
He continued: "I thought I was a couple of lengths clear, and then I heard the commentator say, 'Thomas Hobson is half a length behind!' I thought, 'God', and could just see this head behind me. But I picked him up again and he went again.
"We discussed the ground - it isn't his ideal ground, but the horse has been so fresh at home - he's had two months off - and you can't beat a day like this at Ascot, so we rolled the dice and I'm glad it came off. He is all heart, this horse."
Ireland's multiple champion Jump trainer Willie Mullins is becoming a key figure in front-line Flat races for stayers.
Last week he won the £500,000 Cesarewitch at Newmarket with Low Sun, and for good measure saddled the runner-up, Uradel, and today he came close to landing the G2 £530,000 QIPCO British Chamnpions Long Distance Cup with Thomas Hobson.
The Oisin Murphy-ridden Thomas Hobson (14/1) put down a big challenge to winner Stradivarius (1/1f) in the final furlong, but did not quite have the speed to get through a gap on the rail and was beaten one and a half lengths into second. He finished a length ahead of third-placed Sir Erec (5/1) from Aidan O'Brien's stable.
Mullins said: "Oisin gave him a super ride, full of guts, and stuck to his plan which nearly came off. It did appear to me to be a slowly-run race, but we had one plan and stuck to it.
"We were hoping to be in Melbourne [for the Melbourne Cup in which Thomas Hobson was sixth last year], but we have all next year to look forward to with this horse in these type of races - but we maybe need to avoid this fella [Stradivarius], and not just next season, but for ever.
"I doubt Thomas Hobson will run over hurdles again, and would think we will probably put him away until next year."
Of Low Sun he said: "He was quite sore after the race, but the ground was pretty quick [at Newmarket] and he will be fine in time. Both he and Uradel felt the ground. Low Sun's career over jumps is finished, but Uradel will go hurdling again."
Jockey Oisin Murphy was magnanimous in defeat following 14/1 shot Thomas Hobson's second-placed finish to superstar Stradivarius
Under a steady pace, set by Ryan Moore aboard Flag Of Honour, the two-mile contest turned into a sprint in the home straight and Thomas Hobson, trained by Willie Mullins, ran on well in the closing stages to challenge Stradivarius and Frankie Dettori.
However, Murphy was forced to check his run in the closing stages aboard the Halling gelding as Stradviarius drifted towards the far-side rail.
Thomas Hobson could not make up the deficit and finished a length and a half behind the winner, stretching his unbeaten run to five wins from as many starts this season.
Murphy said: "Thomas Hobson ran well. He relaxed nicely in the race and I was pleased to get the opportunity to ride him.
"No-one wants to finish second. It was a good run and we go onto the next one now."
Aidan O'Brien, trained of the third Sir Erec (5/1) and front-running fourth Flag Of Honour (9/4), said: "They both ran well."
1.25pm £530,000 QIPCO British Champions Long Distance Cup (Group 2) 2M
1 (1) Stradivarius (IRE) John Gosden 9st 7lb Frankie Dettori Evens Fav
2 (4) Thomas Hobson Willie Mullins, Ireland 9st 7lb Oisin Murphy 14/1
3 (6) Sir Erec (IRE) Aidan O'Brien, Ireland 8st 13lb Donnacha O'Brien 5/1
4 (3) Flag of Honour (IRE) Aidan O'Brien, Ireland 8st 13lb Ryan Moore 9/4
5 (2) Desert Skyline (IRE) (Sheepskin C/P) David Elsworth 9st 7lb Gerald Mosse 28/1
6 (5) Cypress Creek (IRE) Aidan O'Brien, Ireland 8st 13lb Wayne Lordan 33/1
Non-Runner: Mount Moriah (Vet's Certificate, Lame)
Winner owned and bred by Bjorn Nielsen
Breeding: 4 ch c Sea The Stars (IRE) - Private Life (FR) (Bering)
Bet With Ascot - Win £1.70; Places £1.10, £3.60; First Two £9.40
Distances: 1½, 1, hd, nk, nse
Time: 3m 37.51s
Fifth QIPCO British Champions Day success for John Gosden
Fifth QIPCO British Champions Day success for Frankie Dettori