A bargain buy has landed trainer Brooke Schreuder her maiden city success.

The victory of Royal Blue in the Cove Hotel Plate at Sandown on Wednesday was 34 year-old Schreuder's fourth career winner.

"Anyone would think it was a Group One race, for us it is," Schreuder said.

Schreuder has been training for four years and after an early success has notched three winners in recent months.

With Daniel Stackhouse aboard, Royal Blue ($11) scored a three-quarter length victory over From Pentridge ($4.80) with Maraudamiss ($5.50) 1-1/4 lengths away third.

Stackhouse was aboard Schreuder's first winner at Mornington in 2012.

Schreuder's mother Susan trained a couple of metropolitan winners when Brooke was at school and has followed her into the racing game, firstly riding trackwork before joining the Tony Noonan stable.

She spent 10 years learning the ropes with Noonan before branching out on her own.

Her recent success commenced with Royal Blue's brother Oklahoma Rocket, breaking through at Wangaratta on Melbourne Cup day last year and with Stellar Princess at Cranbourne in January.

"We vary between three and six in work and do a few pre-trainers as well," Schreuder said.

"We've only got three in work at the moment and they've all won races in the last few months."

Schreuder said Royal Blue and Oklahoma Rocket came as a package deal and have already paid their way.

Royal Blue has picked up around $20,000 in prize money at her last two starts with Oklahoma Rocket, a placegetter at his two starts since winning at Wangaratta, winning just shy of $20,000.

Now a five-year-old, Royal Blue was having her seventh start on Wednesday with the victory coming after the mare had finished third at Pakenham earlier in the month.

Schreuder said Wednesday's maiden race was appealing because it was restricted to four-year-olds and older.

"By coming to town we take away those up-and-coming three-year-olds that keep getting in our way all the time," she said.