ETOBICOKE, Ontario - The 21-1 shot River Rush graduated in style while lowering the nine-furlong Polytrack record in Sunday’s $151,200 Plate Trial Stakes, a prep for the June 24 Queen’s Plate. Jim McAleney broke River Rush from the outside post 11, and they closed stoutly from last along the rail to prevail by 5 1/4 lengths. Incredicat, who set lively fractions over a track that was playing fast, held on for second by a length over Classic Bryce in third. Big Creek was another head back in fourth, and favored Beeker Street finished seventh in the field of Canadian-bred 3-year-olds. The final time, 1:48.97, was .22 quicker than the previous record, set by Catch the Luck in 2009. River Rush paid $44.50. River Rush earned $90,000 for Stronach Stable and trainer Reade Baker, who entered the colt in a maiden race Sunday that failed to fill.  “This horse ran tremendous,” said McAleney. “Reade said if you could save some ground, it would really help, so I opted to do what he suggested. We had just a wonderful trip.”