Great thread Master Steve.
There is probably a distinction between horses that have gone overseas to win a race or races and those that go OS to be based there. Some horses have raced here early in their careers and then moved OS and been renamed. This happens regularly in Hong Kong for example.
Phar Lap probably put in our best OS performance because of what he went through.
In modern times it is hard to go past Better Loosen Up. The Japan Cup was definitely the main OS race that Australians targeted at that time.
Sunline beating Fairy King Prawn is right up there.
Using the other criteria we have a dead heat for me between SYT and then this great horse
Crisp was a champion steeplechase horse. He was a bay thoroughbred gelding that was foaled in 1963 in Australia. In his native country, he won many important jumping races, particularly two-milers, including the Hiskens Steeplechase in 1969 and 1970. So well did he jump, he was nicknamed "The Black Kangaroo". However, Crisp is probably best remembered for his epic contest with Red Rum in the 1973 Grand National in England.
1973 Grand National
Before the off, Crisp was 9/1 joint-favourite with Red Rum to win the National. However, by the time the runners had reached The Chair, Crisp, who was carrying the top weight of 12 stone, had already built up a significant lead and appeared unstoppable. For much of the initial stages, Crisp's closest challenger was Bill Shoemark on Grey Sombrero, but that horse fell (fatally) at The Chair, gifting Crisp an even greater lead which had grown to 20 lengths by the end of the first circuit.
Jockey Pitman later recalled that at the Becher's Brook fence on the second circuit, fallen jockey David Nicholson shouted at him, "Richard, you're 33 lengths clear, kick on and you'll win!" At the same time, he heard the Tannoy commentator Michael O'Hehir declare, "And Red Rum is coming out of the pack, Brian Fletcher is kicking him hard!"
At the 30th and final fence, Crisp was still 15 lengths ahead of Red Rum, who was jockeyed by Fletcher and given 10 stone, 5lb by the handicapper. However, Crisp was beginning to tire badly on the 494-yard run-in, carrying 23lb more than his nearest rival. Red Rum made up considerable ground, and two strides from the finishing post he pipped Crisp by a mere three-quarters of a length to win his first of three Grand National titles.
Even in defeat, Crisp had bettered the Grand National completion time by a full 20 seconds, a record that had stood for the 40 previous years.
Despite Red Rum's unprecedented record in Grand Nationals and securing his place in British sporting history, the 1973 race is as fondly remembered for Crisp's brave run-in defeat as it was for Red Rum's narrow victory. Veteran commentator Jim McGrath called the battle between Red Rum and Crisp among the highlights of all Grand Nationals, and said that Crisp was the unluckiest horse in the race's history.
After the National
Crisp ran only once more after his second-place effort in the 1973 National, at Doncaster the following season. One by one, the other runners were withdrawn, until the race turned into a match, off level weights, between Crisp and Red Rum. Crisp won by 10 lengths, but injured himself in doing so, and was retired.
Pitman, his jockey, said in a 2003 interview that following his retirement from racing, Crisp then hunted for the next eight seasons. He died out hunting, and was buried at the entrance of his then-owner's estate. A cherry tree was planted over the grave, which flowers at Grand National time.