Friendly Island, a 58-1 long shot, gained steadily from the far turn to finish second while early leaders Bordonaro and Attila's Storm tired each other out. Nightmare Affair was third and Bordanaro, fourth.
Thor's Echo, a 4-year-old son of Swiss Yodeler, rated just off the early pace along the inside and moved out along the backstretch, edging closer three-wide on the turn before surging to the front and gaining a clear lead in the upper stretch.
"He really had a good break," jockey Corey Nakatani said, adding his main concern was getting him clear of the rail.
"As I was turning for home, I turned him loose and what a race he ran. I think the key today is that the horses that handle the track the best are going to win," Nakatani said.
Thor's Echo covered the six furlongs in 1:08.8 to take home $1.15 million of the total $2 million purse.
Thor's Echo paid $33.20, $15.80 and $10.20; Friendly Island paid $50 and $32.80; and Nightmare Affair paid $15.20. The $2 Exacta paid $955.40.