The gritty 9yr-old finished strongly on the outside to beat Zacada by a nose in his fifth attempt at the time-honoured $A2 million ($NZ2.1 million) 3200m handicap.
Brian Anderton, who bred Who Shot Thebarman with wife Lorraine, praised trainer Chris Waller for having the stayer peak for an elite event at the ripe age of 9yrs-old.
"It just shows if you look after the horse he will last," Anderton said.
"Though we don’t own the horse, it was a huge thrill. It was a great result for New Zealand all around."
Cambridge trainers Murray Baker and Andrew Forsman produced runner-up Zacada and Matamata galloper Charles Road finished in third.
Former star Otago stayer and fellow White Robe Lodge product Patrick Erin tracked Who Shot Thebarman into the straight and the pair stormed down the outside of the Randwick track.
Patrick Erin could not match the finish of the winner, but finished in a creditable sixth in his first attempt in a group 1 event.
That pleased Anderton, who said Patrick Erin might have performed better if he settled further forward in the running.
"He has got a nice sprint for a furlong and a-half [300m] but he had to sprint three furlongs out," he said.
"He used to to race midfield here. But they probably decided to go back from the draw"
Who Shot Thebarman’s win continued his remarkable staying career that started from humble beginnings.
He was bought from White Robe Lodge for just $10,000 by the Central North Island-based O’Leary family, via studmaster Wayne Stewart.
"The rang Wayne and they said they wanted to buy a nice stayer and they bought him out of the paddock for $10,000," Anderton said.
Who Shot Thebarman’s big race fortunes have been hit by drama recently.
He was a last-minute scratching just days out from last year’s Melbourne Cup. The first running of the 2017 Sydney Cup was declared a no-race when two horses fell, including Who Shot Thebarman, amid safety concerns with the stricken Almoonqith still on the track. The New Zealand-bred stayer finished second when the race was re-run. Along with two Sydney Cup placings, the Yaminin Vital galloper won the 2014 Auckland Cup as well as finishing third in one of his three Melbourne Cup appearances and fifth in another.
"He’s been such a frustrating horse because he’s run so many great seconds and thirds in Sydney Cups and Melbourne Cups," Waller said.
"He’s given us one hell of a ride.
"He’s 9 years old and if Winx is not a pretty good advertisement on how to look after a horse, I think Thebarman takes the cake. That’s the best he’s looked today as a 9yr-old."
Star South Island filly Savvy Coup finished a creditable fifth in the $A1 million Australian Oaks.
The Michael and Matthew Pitman-trained filly finished less than sixth lengths from Waller-trained winner Unforgotten.
• Ireland’s Tiger Roll won the English Grand National in a photo finish from Pleasant Company at Aintree yesterday.
The smallest horse in the field held off a late surge in one of the closest finishes in the historic race watched by an estimated global TV audience of 600 million.
Tiger Roll is owned by Irish businessman Michael O’Leary, the chief executive of Ryanair, and trained by Gordon Elliott, who won his second Grand National.
Winning jockey Davy Russell, of Ireland, was delighted to have won on the 10-1 shot after a thrilling battle down the home straight with Pleasant Company (25-1).
"He’s an unbelievable horse. I’ve won this race a thousand times in my head as a child. It is amazing to have finally won; it is a marvellous event," he said.
Bless The Wings was third at 40-1 with Anibale Fly fourth at 10-1.
