Champion trainer Aidan O'Brien landed his 27th Group One victory of the year as Mendelssohn won the Juvenile Turf at the Breeders' Cup in California.
Jockey Ryan Moore powered Mendelssohn past front runner Sands of Mali after turning into the home straight of the mile race at the Del Mar racetrack.
The 9-2 second-favourite held off late surges from US hope Untamed Domain in second and Voting Control in third.
"He's still learning and he wasn't sure when he was in front," said Moore.
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O'Brien has now won 12 races at the Breeders' Cup meeting since landing his first when Johannesburg won the Juvenile race in 2001.
The victory also extends the world record O'Brien set for Group One winners in a Flat racing season, after he surpassed Bobby Frankel's mark of 25 - set in 2003 - when Saxon Warrior won the Racing Post Trophy at Doncaster on 28 October.
Earlier on Friday in the Juvenile Fillies Turf race, O'Brien saddled September to a third-place finish as Rushing Fall claimed the win to extend its unbeaten record.
September missed the break and was forced to play catch up in what O'Brien labelled a "very rough" race.
O'Brien trains 10 horses which feature across the card at Del Mar on Saturday including War Decree and Churchill in the Breeders' Cup Classic.