Trainer Mac Robertson has been going great at Canterbury Park, and a filly he trains, Ball and Chain, has been going even better. But the hot horse and barn might be up against a slightly superior foe, Ciaran&rsquo;s Prize, in the $40,000 Hoist Her Flag Stakes on Sunday at Canterbury.The Hoist Her Flag is a six&#45;furlong dirt race for older fillies and mares that drew 10 entrants and goes as race 7 on a 10&#45;race afternoon card at Canterbury, where Robertson through Thursday held a seven&#45;win lead in the trainer standings, 38&#45;31, over Robertino Diodoro. Robertson didn&rsquo;t start the meet especially strong, but his stock has done better and better through the summer, and during the last month his Canterbury runners have compiled an excellent 13&#45;4&#45;4 record in 38 starts.That strike rate is high enough to offset the general popularity of Roberton&rsquo;s starters with the betting public, and his $2 win ROI during that period stands at a robust $2.44.But Ball and Chain figures to offer little value, if for no other reason than that there are too many &ldquo;1s&rdquo; dotting her past performances, and casual players will surely gravitate toward a filly from the leading barn who has won four races in a row. Ball and Chain&rsquo;s win streak started last summer at Delaware, and she has won two in a row at this meet, second&#45; and third&#45;level allowance races, the most recent coming June 24. The break between starts poses no great concern, but Ball and Chain is a front&#45;runner drawn inside other speed and is facing generally stronger competition than she&rsquo;s beaten.Ciaran&rsquo;s Prize, on the other hand, drops in class from the $100,000 Saylorville on June 30 at Prairie Meadows, where she was a close, troubled fifth. The race was contested over a muddy strip, and Ciaran&rsquo;s Prize has shown no love for wet tracks in the past. Two starts ago, she won a third&#45;level, six&#45;furlong dirt allowance at Canterbury, where she has a 5&#45;2&#45;1 record from eight starts, and her morning&#45;line odds of 9&#45;2, compared to 7&#45;2 for Ball and Chain, would constitute a fair price. Joel Berndt trains Ciaran&rsquo;s Prize and has another class dropper in the race, Tiz Lately. But Tiz Lately, who changes barns, looked over the top in her last two starts and has done her best work around two turns.