It's a typical story in sports—the star player suffers an injury, so the game trier who usually lingers on the sidelines gets to step up and shine.

When Bloomberg’s top mount Juvina, winner of the inaugural Central Park Grand Prix (N.Y.) in 2014, was injured last year, Lilli, a 12-year-old Brandenburg mare (Lefevre—Dayreen, Diamir), stepped up as the top horse in Bloomberg’s string, and the bay has not disappointed.