Starlust stormed to victory in the Prevagen Breeders' Cup Turf Sprint at Del Mar for the Arc-winning combination of trainer Ralph Beckett and jockey Rossa Ryan.
It looked for all the world as though hot favourite Cogburn would be a blistering winner as he swept clear of Bradsell and the rest of the field under Irad Ortiz Jr, but his early exertions told at the business end as the challengers closed in.
- Classic challenge ends in disappointment for City Of Troy
- The Real Whacker returns to top form with Charlie Hall win
South African raider Isivunguvungu led the chase, but from out of the clouds Ryan powered into contention and Starlust got his head down and in front where it mattered, beating Motorious and AG Bullet.
There was an anxious time for winning connections in the immediate aftermath, however, as Isivunguvungu's rider Manny Franco lodged an objection against the winner for interference, although the stewards did not take long to confirm the result.
Beckett said: "Wow, what a ride he gave him. What a ride - I'm very proud of what he's achieved this year.
"It's extraordinary and I'm really pleased for Jim and Fitri Hay (owners).
"He's a really tough horse who has stormed through. He's really tough, he hasn't had a break all year.
"He's a horse who kind of trains himself. He treated Dubai as a holiday because we couldn't get him to do what we wanted, but he ran well in the Juvenile Turf Sprint last year and we felt if he could stay on their coattails today he could benefit."
On the inquiry, Beckett added: "Flashbacks to Secret Gesture who was taken down in the Beverly D Stakes in 2015. I was concerned because they operate under different rules, but I was glad to get the job done."
Ryan said: "It wasn't the plan, Ralph left it up to me. I jumped well, Ralph said over five try to jump well but after half a furlong take a little pull. Luck was on my side today, the gap opened and he took it well.
"By the top of the straight I thought we would be in the first four, but they couldn't hold that frenetic gallop and it just played into my hands."
George Boughey's filly Believing reared and unseated Ryan Moore in the stalls, leading to the runners being momentarily unloaded. She appeared to emerge unscathed, but was immediately withdrawn.
Rebel's Romance is Turf king again for Appleby and Buick
Rebel's Romance produced a tremendous display at Del Mar to win the Longines Breeders' Cup Turf for a second time.
Charlie Appleby's globetrotting star won this prize two years ago, but whereas James Doyle was in the saddle at Keeneland, it was William Buick who got his moment aboard the big-race favourite this time around in California.
Buick made a key early move to take Rebel's Romance up with the pace, sitting hot on the heels of the leader Cabo Spirit.
Rounding the turn for home Buick asked his mount for maximum effort as he left his rivals flat-footed in the charge for the line before then holding on gamely as Japanese contender Rousham Park finished full of running, having been at the rear alongside Emily Upjohn through the early stages.
It was an 11th Breeders' Cup win for Appleby who once again showed his prowess at this meeting, although there was to be no dream reunion for John Gosden and Frankie Dettori as the well-fancied Emily Upjohn failed to figure.
But much of the gloss was taken off the race with the death of Brian Meehan's Royal Ascot winner Jayarebe, who collapsed on the track after crossing the line, suffering what veterinary officials said was believed to be a "cardiac event".
AAEP on-call veterinarian Dr Al Ruggles told NBC Sports: "We offer our condolences obviously to all the connections. It's suspected to be a cardiac event, they are unusual but can occur. If in fact that is it, post-mortems don't help answer that question generally and they are almost impossible to predict. In a horse that is training well you wouldn't know it."
Of the globetrotting Rebel's Romance, Appleby said: "First and foremost he's very much a yard favourite and he's built up this worldwide fanbase, most notable when he went to Hong Kong when everybody knew him.
"Throughout the race I was pleased with where he was and pleased he made the move when he did. He's a superstar, he really is. When you watch him run, you really feel it - you want him to win.
"To be campaigned at that level for the time he has takes a lot of guts."
He went on: "He (Buick) was pretty confident we had got the job done, but he was idling because we'd been out there for so long.
"This fella owes us nothing. Obviously we would like to take him back to Dubai for the Sheema Classic, he's a real star and draws all the media attention.
"With a horse like him he takes the pressure off you. When you roll a horse like him out you know you are going to get everything from him.
Like any athlete it takes a good one to knock him off his peg
"We planned to come back for the Turf last year, but he'd lost all of his mojo.
"We had to build him back up. Like any athlete it takes a good one to knock him off his peg."
Emily Upjohn could never get in a blow under Frankie Dettori, finding little racing room, and John Gosden, who trains alongside his son, Thady, confirmed she had run her last race.
He said: "She hasn't had a hard race, but that's it now, she's going into retirement."
Cinderella's Dream just edged out in Filly And Mare Turf
Time ran out for Charlie Appleby's Cinderella's Dream in the Maker's Mark Breeders' Cup Filly & Mare Turf with her late thrust in vain, as Moira landed the spoils at Del Mar.
The Moulton Paddocks handler won this contest with Wuheida in 2017, but there was not to be a repeat with both his Cinderella's Dream and Beautiful Love out of luck in California.
Kevin Attard's runner had finished behind stablemate Full Count Felicia in Woodbine's E P Taylor Stakes in September, but with the latter setting the pace, Flavien Pratt aboard the Canadian-trained scorer was able to position his mount in the perfect position as the contest entered the final turn.
With William Buick on Cinderella's Dream trapped on the inside with nowhere to go, Pratt and Moira were able to set sail for home unchallenged and although the Godolphin-owned favourite finished with a flourish, Moira could not be reeled in.
Didia was a close-up third with Cinderella's Dream's stablemate Beautiful Love, in the hands of Oisin Murphy, fourth.
Attard said: "She's just a very special horse and very deserving of this. I'm lost for words and emotional right now.
"It's a dream come true and I'm so happy for her because she's had some tough luck in Grade Ones and today she has proved she is the best turf horse in the world.
"These are things you dream of as a kid, wanting to be a trainer. I have to thank the connections for entrusting me with her and obviously my staff for bringing me to this point in my career. It's a team effort and I have a lot of people behind me and obviously the jockey did a great job."
On the performance of the runner-up, Buick said: "I had a good trip off a slow pace. I decided to wait, but I didn't get the split in time.
"She hadn't done the trip before so I tried to save everything I could."