Making his first start in the United States and on dirt, Wilko has a pedigree that made you think he would like it, being by 1998 Breeders' Cup Classic winner Awesome Again . His dam's side says turf though; he was produced from the Indian Ridge mare Native Roots.
The big horse from Bob Baffert's barn, 2-1 favorite Roman Ruler, failed to fire, finishing fifth while never in the running.
The time for the 1 1/16-mile race was 1:42.09.
Another longshot Twice Unbridled set the early pace while Frankie Dettori had Wilko sitting second. Consolidator and Sun King were also running with the leaders early as they went a quarter in :23.54, a half in :47.49, and six furlongs in 1:11.25.
Dettori let Wilko drop back a bit at the quarter pole, but he then came on again to win by three-quarters of a length. Afleet Alex was running at the same time as the winner and got second, a quarter of a length ahead of Sun King.
"I can't believe it," Dettori said. "I mean the horse worked well on the dirt but we were just hoping to hit the board.
"He got a great jump but I got outpaced to the quarter pole. But they stopped so I pulled him out (side) straightaway."
Bred in Kentucky by Ro Parra, Wilko is owned by J. Paul Reddam, who bought 75% of the colt earlier this month, and Englishwoman Susan Roy, who won the 2002 Belmont Stakes (gr. I) with Sarava. All 10 of his prior races were in England, where he is based with trainer Jeremy Noseda.
"I didn't think we had anything to lose. I thought we could get a piece of it," Noseda said.
The chestnut colt won a minor stakes at Yarmouth in early August but in his two starts before shipping, group II races at Doncaster and Ascot, he finished fourth and third.
Wilko paid the third biggest amount in BC Juvenile history – $58.60, $18.20, and $6.20. Afleet Alex returned $5 and $3.60. Sun King was worth $5.60.
The biggest Juvenile upset was 41-1 shot Action This Day last year at Santa Anita. Anees was 30-1 when he won in 1999 at Gulfstream Park.
Wilko is the third European horse in 21 years to win the Juvenile, following in the footsteps of Arazi in 1991 and Johannesburg in 2001. He'll be transferred to Southern California conditioner Craig Dollase to resume his career next year.
Tim Ritchey, who trained Afleet Alex, said had a rought time after stumbling coming out of the gate.
"He showed his heart, he said. "I thought he was going to get there, but the other horse got him."
Consolidator ran fourth, with Roman Ruler, Proud Accolade, Twice Unbridled and Scandinavia trailing.
Baffert said he is still trying to find the key with his talented Roman Ruler.
"Corey said he wasn't getting a hold of the track," Baffert said. "You've got to be aggressive with this horse. You have to put it to him. He's got to be ridden a certain way and we are trying figure out his style."
Nakatani added, "He's better than that. He never tried. His head was in the air the whole way."