Although extremely green late, Bob Baffert’s Authentic stamped himself as a top tier Derby contender with a powerful gate to wire triumph in Saturday’s Grade III, $100,000 Sham Stakes at Santa Anita. Ridden by Drayden Van Dyke the Kentucky-bred colt by Into Mischief got a flat mile in 1:37.57. Sent from his rail post position, Authentic was all business on the front end until he approached the furlong pole, when he began to race erratically, altering course and nearly brushing the inner…