"This is definitely the hardest race in this state to win," Bob Peters told Sky Thoroughbred Central.

"This is the race we have aimed for ever since she was foaled and we have looked after her."

Pike, who is also the leading rider in the country, said the early part of the race was nerve-racking.

"I was terrified in the run and I was starting to go through my excuses," he said.

"I had to make the best of a bad situation and I followed Gatting and then the gap came.

"She was at her peak today. She was primed for this."

Grant Williams was thrilled to win the race but more thrilled for the mare.

"The two horses who finished second and third are hard to get past," he said.

"She is all class."

While Galaxy Star won the group 1 feature, the team also celebrated the win of Arcadia Queen in the WA Guineas with a chance they could clash at the highest level in the Kingston Town Stakes next month.

Arcadia Queen was the $1.90 favourite and had a more comfortable time during the race, running out a three length winner over Lady Cosmology.

Pike rode four winners in the day's last five races.

AAP