Nando Parrado sprang a 150-1 upset in the Coventry Stakes on the final afternoon of Royal Ascot.
Beaten into fifth on his racecourse debut at Newmarket earlier this month, Clive Cox's charge showed plenty of improvement to bag this six-furlong contest.
Partnered by Adam Kirby, Nando Parrado was in front with a couple of furlongs to run always looked like holding the late thrust of Qaader (3-1).
Saeiqa (25-1) finished third, but favourite Admiral Nelson was well beaten.
Cox said: "I was just saying it is not a shock - the price was a shock. He is a proper horse and we loved him from the start.
"It was always the plan to come here, it was just a sideways step on his first run. He came home and thrived from there.
"When the rain came earlier in the week, I knew he would be better on good or slower ground than quicker ground.
"There was a little bit of wavering from the owner. We put him in, then took him out the other morning as he was not sure we could go for the Coventry, but I persuaded him to get him back in there, so I'm sure he won't mind me telling you that."
A huge upset in the Coventry Stakes as Nando Parrado wins at 150/1!
— Ascot Racecourse (@Ascot) June 20, 2020
The biggest priced winner in Royal Ascot history! 😮#RoyalAscot pic.twitter.com/m6NDEILrdC
Chiefofchiefs (20-1) won the Silver Wokingham Handicap which opened the card.
Trained by Charlie Fellowes and ridden by William Buick, the seven-year-old headed Nahaarr inside the final furlong before stretching out to take victory on the line.
Burmese Waltz (22-1) grabbed second in the dying strides, with Nahaarr (4-1) back in third and Louie De Palma (25-1) fourth in the six-furlong heat, a consolation event for the Wokingham.
Fellowes said: "That's the worst training performance you'll see here all week. He's a seven-year-old, yet that is the first time I've run him over six furlongs.
"I've called him every name under the sun thinking he wasn't putting everything in, yet actually it's all been my fault. All's well that ends well.
"I'm over the moon for his owner/breeders who only have a couple of mares. I know how much this will mean to them - we need people like them in the game and I'm over the moon for the lads in the yard to have two winners as the last few months have been tough.
"We put a visor on him in Dubai and Richard Mullen told us we were running him over the wrong trip, so we brought him back to six. Also he has some good runs at Ascot to his name - the track suits him, like it does a lot of mine.
"To have three winners here in two years, I feel very lucky.
"We came here thinking we had two decent chances with King Ottokar and First Prophet. Those two it didn't fall right for, but I actually had a few quid on this lad as he was 50-1 last night, which was a bit insulting."
Buick said: "It's a stiff six furlongs and in the ground it takes a bit of getting. We went a good pace which suited, we got some nice cover and the race panned out perfectly.
"He had some smart form in the book if you looked back far enough. As long as he didn't get outpaced early, I fancied him to run well."
A flying start to the final day of Royal Ascot for jockey William Buick as he partners Chiefofchiefs to win the Silver Wokingham Handicap
— Ascot Racecourse (@Ascot) June 20, 2020
And it's a second winner of the week for trainer @FellowesRacing 🏆🏆#RoyalAscot pic.twitter.com/Bb6y9P8Bmu
Campanelle (9-2) gave American trainer Wesley Ward another Royal Ascot win in the Queen Mary Stakes.
Ward had trained 10 previous victors at the meeting and Campanelle gave him an 11th success with a gutsy performance in the five-furlong heat.
Frankie Dettori produced her late in the day to collar Sacred (5-1) inside the distance and edge clear at the post.
Caroline Dale (100-1) was prominent throughout and clung on for third to make a mockery of her odds.
Dettori said: "Having an outside draw, you have the luxury of deciding when you want to go. I thought I'd get my filly organised to the two and I had plenty of horse left.
"She's very sensible, she's not a tearaway. I was able to control her energy and when I asked her to quicken she quickened really well.
"When I ride for Wesley he leaves it up to me, his horses are always very well schooled and know their job. A lot of the time they make the lead, but we don't have to make the lead all the time, it depends how the race develops.
"I'm pleased, Wesley sent horses and has had one winner and two seconds. Barbara (Banke, Stonestreet Stables) is a big supporter of mine and so is Wesley, I wish they were here to celebrate with me but we will get together very soon."
Ward said: "We were narrowly beaten last year and we've had some near misses this year so we needed that.
"The owners are big supporters of mine, they obviously had Lady Aurelia with me, and with Frankie, who rode such a brilliant race - it's great.
"My assistant has done a great job, I've such a great team, and words can't describe how I feel right now, it means more given this is not a normal year."
A superb performance from Campanelle from stall one as she quickens smartly to land the Queen Mary Stakes 🏆
— Ascot Racecourse (@Ascot) June 20, 2020
An 11th Royal Ascot winner for US trainer Wesley Ward 🇺🇸
And a fourth winner of the week for @FrankieDettori #RoyalAscot pic.twitter.com/SO34IfYTFC
Kevin Stott and Kevin Ryan quickly made it a famous double as Hey Jonesy (18-1) followed up Hello Youmzain's Diamond Jubilee Stakes success by holding off the late charge of Summerghand (15-2) in the Wokingham Handicap.
The winner was clearly in front on the far side inside the final furlong, but Summerghand was absolutely flying down the stands side under James Doyle.
He was closing with every stride and the pair flashed past the post together, with a photo confirming Hey Jonesy had just held on. Spanish City (16-1) finished third, with Gulliver (12-1) fourth.
Stott said: "As a two-year-old we had high expectations for him, but he lost his way a bit at three, even though he ran a good race in the Commonwealth Cup.
"We tried him over different trips, he ran on Tuesday when he wasn't happy and he needed some encouragement which the blinkers gave him."
Adam Ryan said: "For whatever reason, the last sort of six months he hasn't clicked, but he came back sound after Tuesday and we thought running quickly might spark him back to life.
"Kevin gave him a positive ride and it's worked. It was tough watching the final furlong with them closing on him.
"He had some class form as a two-year-old and it's all about catching him right.
"We won't ever forget this last half hour, that's for sure. The last few months have been tough for everyone but there were no complaints from the staff - this is down to them."
An incredible finish to the Wokingham Stakes as Hey Jonesy edges out Summerghand by a nose! 👀#RoyalAscot pic.twitter.com/uxUecMq0AR
— Ascot Racecourse (@Ascot) June 20, 2020