ARLINGTON HEIGHTS, Ill. - Class drops could hold the key to the Grade 3, $150,000 Matron, a 1 1/8-mile Polytrack race for older fillies and mares Saturday at Arlington Park. Ausus made her most recent start in the Grade 1 Jenny Wiley Stakes, finishing an even fifth behind Centre Court, who could be the best female grass horse in the country right now. Imposing Grace, meanwhile, hooked up with the likes of Authenticity, On Fire Baby, and Believe You Can when she finished sixth in the Grade 2 La Troienne Stakes. The pair of class-droppers actually squared off in an Arlington Polytrack allowance race last summer. Ausus got the better of Imposing Grace then, and might do so again in the Matron. Centre Court is not the only high-class filly Ausus has faced in recent starts: Three races ago, in the Marie Krantz at Fair Grounds, she launched a solid stretch run that propelled her within 1 3/4 lengths of a loose-on-the-lead Daisy Devine, who won last year’s Jenny Wiley. Ausus, a 4-year-old Shadwell Farm homebred by Invasor, has the look of an improving horse. “I sure think she has gotten better with age, and I don’t know if she’s better on grass, but I guess we’re going to find out,” said trainer Dan Peitz. “I thought this was a pretty good spot for her. Last year at Arlington, it was all one-turn races, and I’ve actually been wanting to see her at a mile and a quarter, a mile and three-eighths.” Imposing Grace, who gets off the rail for the first time in three starts, chased Believe You Can in Fair Grounds dirt races earlier this year, and there are no fillies of that quality in the Matron. Hooh Why, the 3-1 morning-line favorite, is a 7-year-old with none of the upside of Ausus or Imposing Grace, but 4-year-old Ice Cream Silence might yet have room to improve. She was a game front-end winner of the Doubledogdare at Keeneland last out, albeit with an assist from leading on a slow pace. Brazilian rider hits town Joao Moreira, a 30-year-old Brazilian who has dominated the jockey colony in Singapore the last three years, is scheduled to make his North American riding debut on Saturday at Arlington. Moreira was named on three horses, including Sisterhood in the Matron, and will go on to ride at Churchill Downs on Sunday and Monday before returning to Singapore next week.