Rosehill's Rawson Stakes is the race which saw Australia's greatest ever upset in a horse race when Ajax was beaten at 40-1 on in 1939.The upset in the 100th edition could boast nothing of those proportions, but few could have foreseen that Australia's leading moneywinner, Northerly, would lose at his belated Sydney debut in the $400,000 (Australian funds) event.But in seeking a ninth group I win, the 6 year-old's first race on a right-handed oval saw him beaten by a short half head.Republic Lass (7-1) collared Northerly after the $8 million–plus winner saw off Freemason just inside the 200 meters pole. His battle with the other veteran lasted longer than Pat Payne would have liked -- never mind those who bet at 2-5.No sooner had Northerly fended off Freemason than he was set upon by last year's Australian Oaks (Aust-I) winner. The filly had far more momentum 100 meters out and appeared certain to steam past him and win easily.Northerly eyeballed her and then moved out two or three horses to get up close and personal. Republic Lass kept finding for Glen Boss, but Northerly was now on the attack. Her neck lead had almost vanished as they reached the wire.Freemason finished third, seemingly unnoticed, 2 1/2 lengths away. The 2,000 meters in 2:01 was 76/100ths of a second wide of the race mark.Republic Lass was bred and is raced by Dean Fleming owner of Eliza Park Stud in Victoria. His father, Jim, a former chairman of Rosehill owners the Sydney Turf Club, bred Bint Marscay, dam of the day's other major winner Bollinger.Republic Lass is by Canny lad and her second group I success advanced her earnings to $1.3 million in winning six from 20 starts. She is just the third distaffer to collect the Rawson in the past 25 years. It was the third win in the past four editions by Guy Walter. He also prepared Tie the Knot, left with two Rawsons after one was taken away for interference.Carnegie Express worked home solidly to take fourth, but Don Eduardo, who pipped him in the Australian Derby (Aust-I) 12 months ago, will need the sanction of his owner Eduardo Cojuangco to race on. The Zabeel colt came in last of the eight runners, almost 12 lengths from the first pair.