Complex sentence: Espinoza, who won the 2002 Kentucky Derby on War Emblem, rode California Chrome to win the King Glorious Stakes on December 22 by lengths, becoming the final stakes winner at Hollywood Park Racetrack, which held its last races that day.
Split into simpler sentences: Espinoza, who won the 2002 Kentucky Derby on War Emblem, rode California Chrome to win the King Glorious Stakes on December 22 by lengths. The horse was, incidentally, the final stakes winner at Hollywood Park Racetrack, which held its last races that day.