ARCADIA, Calif. — Call it Selection Saturday — three important prep races run in a stretch of 90 minutes to determine which horses have a realistic chance to capture the 140th running of the Kentucky Derby next month. When it was over, there was little doubt about the overwhelming favorite at this moment.

His name is Dortmund, a strapping and fast colt who decimated five rivals here in the Santa Anita Derby to remain undefeated, which was no small thing for his owner, Kaleem Shah. Before the race, Shah said that he was not only nervous for the first time but also thinking about history.

About two previous Kentucky Derby victors, to be exact: Smarty Jones (2004) and Seattle Slew (1977).

“I was looking to do what Seattle Slew did when he went to the Derby 6 for 6, Smarty Jones went there 6 for 6,” Shah said. “It was critically important that he move forward, not regress.”