The 4-year-old Irish-bred filly Midnight Horizon has had a challenging build-up to her American debut in an allowance race at six furlongs on turf at Santa Anita on Sunday. Earlier this month, Midnight Horizon worked five furlongs in 58 seconds on the infield synthetic training track in company with the graded stakes winner El Potente. El Potente, a candidate for the Grade 1 Shoemaker Mile on turf at Santa Anita on May 25, and Midnight Horizon are trained by Dan Blacker. “She impressed me enough in her works I felt she was ready to work with a good horse,” Blacker said of Midnight Horizon. “She passed the test. It’s a positive sign, but a workout is a workout and not a race.” :: Play Santa Anita racing with confidence. Get DRF Past Performances, Clocker Reports, and more. Midnight Horizon is part of a field of nine in Sunday’s seventh race. The opposition includes Rethink, who was third in a race at this level at about 6 1/2 furlongs on the hillside turf course on April 18; Miyako, who won a starter allowance at six furlongs on turf earlier this year; and Not a Sinner, the winner of a starter allowance-optional claimer at six furlongs on turf in March. Midnight Horizon has won 2 of 6 starts, with both wins in her final races in Ireland in six-furlong handicaps on turf in a nine-day span last June. Midnight Horizon arrived in California last summer but was given a rest. “We needed to give her some time,” Blacker said. Since late March, Midnight Horizon has had eight workouts on the synthetic training track. She races for a partnership led by Blinkers On Racing. On Sunday, Blacker is banking on runners such as Miyako and Forum Confidential, the winner of a recent 1,000-yard race at Los Alamitos, to set a quick tempo that will help Midnight Horizon’s closing style. “If the race sets up for her, she’ll be tough,” Blacker said. “Hopefully, the race has a bit of pace.” :: Want to learn more about handicapping and wagering? Check out DRF's Handicapping 101 and Wagering 101 pages.