The Bob and Sandra Peters owned Silverstream claimed another feature race win at Ascot on Perth on Saturday when upsetting the favourite Scales of Justice to win the Group II WATC Lee Steere Stakes.

The six year-old Al Maher mare is in career best form and charged home from the tail of the field to win the 1400 metre sprint by a head.

It was the third stakes success for the Adam Durrant-trained mare who has the $1 million Group I WATC Railway Stakes in her sights.

“She had a go at the mares’ (series) last year. She’s six now and hasn’t got long to go so we’ll have a try (in the Railway Stakes),” owner Bob Peters told the West Australian.

Winning rider William Pike said he was confident in the run but it was a near thing in the end.

“I rode to have the last say and we were able to get it today,” he said.

“I was sort of half confident I was going to get there but the line was coming up pretty quick, so I had to stick my head out a bit.”

Purchased for $320,000 by Belmont Bloodstock from the Yarraman Park draft at the 2013 Inglis Australian Easter Yearling Sale, Silverstream is the most expensive yearling for her sire ever sold but she has proved her worth with a record of eight wins and five placings from 24 starts with earnings of $552,300.

A full sister to Group III AJC Adrian Knox Stakes winner Speedy Natalie, Silverstream was co-bred by Arthur Mitchell and foaled and raised at Yarraman. She one of seven winners from stakes-winning Brocco (USA) mare Speedy Bell, who is also the dam of stakes-winner Calanda.

Speedy Bell died last year and her final foal, a colt by I Am Invincible, made $320,000 to the bid of the Hong Kong Jockey Inglis Easter this year.