The move from synthetics to dirt was a boon for Southern California shipper River Echo, who pulled a 19-1 upset Sunday in the $100,000 Premiere Cup Handicap at Zia Park. The six-furlong race opened the stakes schedule at the Hobbs, N.M., track, which runs a mixed meet for Thoroughbreds and Quarter Horses. River Echo ($41) stalked in third early and overtook leaders Ez Dreamer and Greeley’s Conquest to cover the distance in 1:09.24. Alejandro Medellin was aboard for trainer Henry Dominguez. River Echo was making his first start at Zia after finishing seventh in a $25,000 optional claiming allowance over Del Mar’s synthetic surface Aug. 29. He had been stakes placed in Southern California earlier in his career, and picked up his first stakes win in the Premiere Cup. “He’s an old-class horse who liked the dirt, so we thought he would do well here when he could get back on the dirt,” said Dominguez, who trains River Echo for J. Kirk and Judy Robison. River Echo won by 1 1/4 lengths over E Z Dreamer, who won last year’s Premiere Cup. Greeley’s Conquest, the favorite, finished fourth Sunday.