The Juan Navarro owned, Slippery Sam scored an upset victory in Yesterday's feature event over 1,350 metres at Santa Rosa Park, Arima.The Derick Mosca trained colt scored at odds of 10-1 to register another victory for the year. Richard Perez rode an aggressive race, keeping Slippery Sam at the front end, before going for home 500 metres out.At the corner, the highly regarded Rock Movistar was bought to challenge by Prayven Badrie but try as he did, he could not peg back Slippery Sam. Perez kept getting more from his mount, which hit the line winning by a short head.Mike's Sugar stayed on for third with favourite, Undulation fourth.Slippery Sam recorded the time of 1:20.3 for the trip. Riding honours for the day went to Richard Perez, who rode two winners, Don't Blink and Slippery Sam. No Trainer was able to land two winners on the 7 race card.Racing continues next week Saturday at Santa Rosa Park.