Pre-entries for the 2018 Classic were announced on October 24 with the post position draw held on October 29. The field for the 2018 Classic was weakened when the likely Horse of the Year, Justify, was retired in July. Justify won the American Triple Crown and his connections were hoping to complete the Grand Slam of Thoroughbred racing by also winning the Classic. However, a slight injury derailed those plans. Good Magic, winner of the Haskell Invitational and the 2017 champion two-year-old, was also retired due to injury. The connections of another leading contender, Whitney Stakes winner Diversify, opted to bypass the Classic when his trainer, Rick Violette, became ill and subsequently died. In their absence, the race was considered highly competitive. Nineteen horses were pre-entered on October 24, though several of those had first preference in other races on the Breeders' Cup card. The leading contenders included:
A poor start resulted in the horses with inside posts all being bumped and losing position. Yoshida and Lone Sailor also broke poorly and settled at the back of the pack. On the other hand, Mendelssohn broke well from post position nine and worked his way to the rail. He took the lead going into the first turn over McKinzie, with West Coast and Thunder Snow close behind. Accelerate, who broke from the outside post position, was urged by jockey Joel Rosario to get early position, then rated in fifth place around the first turn and down the backstretch. After starting his move down the far turn, he drew by Mendelssohn at the top of the stretch, then turned back a bid from Thunder Snow. Gunnevera mounted a late charge to take second place, a length behind Accelerate. Accelerate's trainer John Sadler earned his first win at the Breeders' Cup in 45 attempts spread out over 30 years. "I'm thrilled," said Sadler. "In order to get the big one, you couldn't ask for a better day." With the win, Accelerate solidified his chances to win the Eclipse Award for Champion Older Male Dirt Horse, and sparked a debate in the Horse of the Year category. Accelerate won five Grade I races over the year, compared to four such wins for Justify. Justify's wins included the American Triple Crown, while Accelerate became the first horse to win the Santa Anita Handicap, Gold Cup at Santa Anita, Pacific Classic and Awesome Again, in addition to the Breeders' Cup Classic. "This horse is special. He's showed up every time. He's danced every dance. He's been solid," said his owner Kosta Hronis. "This is Horse of the Year. It's a body of work, and what he has done in the last 12 months, I think he's well deserved to be of that honor. There's no doubt." Antonio Sano was equally proud of his trainee, Gunnevera. "He ran second and had lost a couple lengths at the start," he pointed out. "They sandwiched my horse. Every time we are closer and closer to winning a grade 1. He's going to race in 2019 and will point to the Pegasus." That race is also under consideration for Accelerate, who will then head off to stud.
