After vowing earlier this week that Ka Ying Rising (Shamexpress) would not be chasing any more track records in defence of his title in the HK$24-million G1 Chairman's Sprint Prize, jockey Zac Purton will be only too happy to have been proven wrong. That's because the 5-year-old wunder-sprinter made the 1200-metre contest his 20th straight success, lowering his own mark by 0.02 and sweeping the Hong Kong Sprint Series for the second straight season. It has been just short of 500 days since Ka Ying Rising was last defeated in...