Who can stop super juvenile Bustling from winning the second-leg of a feature two-year-old double at Ascot on Saturday?

After demolishing rivals in the Karrakatta Plate (1200m) by a whopping 4 ¼ lengths, Bustling looks to have a stranglehold on the WA Sire's (1400m).

Bustling is all the rage as the $1.40 favourite with Tabtouch and winning the Sires's would enhance his status as the next big thing of WA racing.

The Russell Stewart-trained Golden Kathleen and Blue Rocket for brothers Dan and Ben Pearce are the only other runners at single figure odds.

Costing a modest $3000 as a yearling, Golden Kathleen gave her owners an immediate return when scoring impressively on debut at Bunbury.

The daughter of Leonardo da Hinchi further impressed at her next start in the Gimcrack Stakes (1100m) when she rattled home from last for second.

Golden Kathleen also made ground from the back of the field in the Karrakatta Plate (1200m), clocking the fastest last 600m of the race when sixth.

With Bustling's market dominance, the WA Sires' Produce Stakes looms as a David versus Goliath battle, but Stewart is not backing away from his filly.

The former jockey says Golden Kathleen will be at her peak in the Sires' and he's quietly confident she can burst the bubble of Bustling.

"My word I can, my word," Stewart said to The Races WA.

"Her last two 600 metres have been as good as his (Bustler) if not better.

"And she's had traffic problems, red lights and more traffic problems.

"He's been in the clear running his last 600m as he likes.

"In the Gimcrack she only got out 100 out.

"So, how well is she going."

The barrier 'gods' have been kinder to Golden Kathleen in the Sires' after wide gates in the Gimcrack Stakes and Karrakatta Plate.

With Steven Parnham aboard for his first official race ride, Golden Kathleen will jump from barrier one in the field of nine starters.

In an attempt to bridge the gap on Bustling, Stewart has gone for a minor gear change to extract any competitive advantage he can find.

"Barrier one doesn't pose a problem and a subtle little gear change, a set of winkers," Stewart said.

"I didn't think she needed anything, but I thought let's just try something where I can find that one percent that I need."

While pushing the case for Golden Kathleen, Stewart is respectful of what Bustling's been able to achieve early in his career.

He's looking forward to the contest and says the Dan Morton-trained gelding deserves the hype..

"Look, don't get me wrong, Bustling is top of the Wozza," Stewart said.

"But, I've got a filly who gets 2kg off him, I'm pretty happy.

"I think the race maps well and she's in good order.

"She's even better than what she was before the Karrakatta.

"The data says she recovered better and she'll get the 1400m the way she's been running home.

"I'm actually looking forward to it."

After she opened at $4.80 Wednesday, Golden Kathleen has eased to $5.50.

Bustling is in from $1.45 to $1.40.