The packed two-day slate features the most races in North America, and the best horses in the world congregate to race.
"We've just got to keep him healthy", he said of the horse, who improved to 4-0 in his young career.
The dual Arc victor Enable will be a warm order to become the first horse to win an Arc and Breeders' Cup in the same year rather than the ninth to have failed. "I had to rein him back and basically restart the race", the rider said.
The hot prospect for the $3.3 million first prize in the one-and-a-quarter mile race - the same distance as the Kentucky Derby - is the John Sadler-trained Accelerate, a multiple victor at the top level in the US.
Enable made history at Churchill Downs in Saturday's US$4m Grade 1 Breeders' Cup Turf (1m4f).
Ridden by Joel Rosario, Game Winner covered 1 1/16 miles in 1:43.67 and paid $4, $3.20 and $2.80.
"He broke really well", Rosario said of Accelerate.
Gunnevera returned $21.80 and $11.80, while Thunder Snow paid $8 in redeeming himself at Churchill Downs after a last-place finish in the 2017 Kentucky Derby.
Trained in Southern California by last year's Triple Crown victor, Bob Baffert, Game victor got a bit of a slow start in the Juvenile and jockey Joel Rosario had to settle him behind the leaders early.
In the first running of the race as an official part of the Breeders' Cup programme - rather than on the undercard - the Todd Pletcher-trained juvenile broke smartly under Javier Castellano, with only Chelsea Cloisters going with him in the early stages.
Gunnevera, Thunder Snow and early pace setter Mendelssohn made things interesting in a wide-open field, an upside to the absence of horse racing's 13th Triple Crown victor from the Classic.
Bob Baffert, Triple Crown trainer for both American Pharoah and Justify, has won three of the last four editions of the Breeders' Cup Classic.
Thunder Snow, the horse that beat West Coast in the Dubai World Cup, has done the majority of his racing overseas. And it followed other notable performances on the second day of the $30 million championships.
The John Gosden-trained filly didn't get her four-year-old season underway until September thanks to a leg injury, but that didn't stop the bay star from winning a second straight Arc on October 7 with Frankie Dettori in the irons.
Bulletin, making just his second career start, shot out of the gate like a bullet and was never behind, winning the first running of the Juvenile Turf Sprint by 2 3/4 lengths.
This race for fillies and mares features the two most recent Kentucky Oaks winners in Monomoy Girl and Abel Tasman.
Now she can become the first horse to win the Arc and the Breeders' Cup Turf in the same season. Discreet Lover is his first graded stakes victor and won the Grade 1 Jockey Club Gold Cup in his last start at odds of 45-1. "Thank the lord that this horse came through and everything went well for us today because these races are hard to win".