Trainer Guy Walter achieved a rare group I trifecta in Sydney March 28.Runners from his barn dominated the $2 million (Australian funds) Doncaster Handicap (Aust-I) at Randwick, filling all three placings. Walter's first success in the feature has no precedent in 139 editions of Australian's most famous mile.A 1-2-3 result in a group I race for a stable is rare, achieved just three times in Australia since first recorded in the 1919 Caulfield Cup by Dick Bradfield. A previous trifecta had been achieved by Walter rival Gai Waterhouse in the 2001 Golden Slipper Stakes (Aust-I). Late master trainer Colin Hayes did it in the 1977 South Australian Oaks.Patezza arrived first by a length at 20-1 under Melbourne jockey Danny Nikolic, a long head separating the next pair, Court's in Session (6-1) and Danni Martine (9-1). The only other Walter entry was withdrawn the morning of the race.Without detracting from the performance of the winner, Court's in Session was one of the better-beaten performances in recent years. Fresh from his grand success in the George Ryder (Aust-I), the gelded 5-year-old contested the lead for the entire 1,600 meters and went down fighting for Glen Boss.Patezza stopped the clock at 1:35.98 on a soggy track rated slow. Despite being almost three seconds wide of the track mark of 1:33.13, the pace generated by the runner-up's duel with Osca Warrior was very genuine. It also left him a sitting shot in the stretch. Of the 15 chasers at the top of the lane, however, only Patezza's sweeping run out wide was able to claim him and reverse the Ryder result.The win ended several years of frustration for Patezza's breeder Pat Shanahan, his co-owner Terry Carr, and Walter. His win in the Newcastle Newmarket (Aust-III) early in March was the horse's first since he split a cannon bone almost three years ago.A son of 1987 W.S. Cox Plate winner Rubiton, Patezza has won eight races and $1.6 million. He has also placed in another 11 of 27 career starts.Walter trained champion weight-for-age horse Tie the Knot from his Warwick Farm in western Sydney. More recently he polished other gifted multi-millionaires in Defier and Spinning Hill, both retired.