Vallestina won her debut at Canterbury Park by 17 1-2 lengths on June 24, prompting a private acquisition from Eclipse Thoroughbred Partners.
The filly rewarded her new owners and trainer - Michael McCarthy - with a two-length win in her California debut in a starter allowance at six furlongs for fillies and mares.
Ridden by Flavien Prat, Vallestina disputed the pace with Candy Boss for the first half-mile before edging clear. She won by two lengths over Candy Boss.
The purse was $35,000, meaning Vallestina earned $21,000 of the main purse. There were bonuses for a shipper racing in California for the first time - $6,300 from a 30 percent bonus through Del Mar's Ship and Win program, and $1,500 for a first-time appearance bonus at Del Mar.
All told, the winners's share was worth $28,800.