The Ingham name is known equally for its success on the racecourse as its poultry empire yet the family celebrated their Coolmore Stud Stakes victory like it was their first.

Billionaire Bob Ingham's children were whooping and jumping for joy at Flemington after Japonisme delivered their first Group One win under the Ingham racing banner and in their partnership with trainer Chris Waller.

Daughter Lyn Ingham was so overjoyed she was almost lost for words.

"I don't think I can speak. I can't believe it," she said.

"I knew we were going to do it one day. I hoped it was going to be soon."

Brother John Ingham was equally excited that Waller, a winner of more than 50 Group One races, could give the children their first.

"Here we are at Flemington, the main house in the big week getting a Group One - some fairytale stuff."

The Inghams made their fortune through their poultry empire and enjoyed success in many major races through the 1980s, 1990s and 2000s, including with champions Octagonal and Lonhro.

Bob Ingham, who watched Saturday's race at home, sold his Woodlands racing and breeding operation to the ruler of Dubai, Sheikh Mohammed, for a reported $500 million in 2008.

He passed on the Ingham racing banner and its well-known cerise colours to his children Lyn, Robby, Debbie and John, with Waller taking charge of a small band of horses.

"It's very, very special," Lyn Ingham said of Japonisme's win.

"It is a double bonus to breed him."

While racing runs in the family, she said they always celebrated their wins whether it be a Group One at Flemington or a provincial NSW race.

"If it's a win at Kembla Grange or it's winning the Coolmore at Flemington, a win is special to us because that's what we have horses for. We have horses to race them and hopefully they win.

"To have Jappy win the Coolmore is just, I don't know, I can't put it into words. It's just unbelievable."

Japonisme went into the race as an outsider to short-priced favourite Exosphere, who finished fourth.

"I've said to everybody today `if anybody knows that a horse can be beaten' - as in Exosphere - `we know they can be beaten'," Lyn Ingham said.

"We had Lonhro beaten. We had Octagonal beaten.

"We've beaten him. Wonderful.

"Dad, we did it Dad."