Clark, 25, has accepted an invitation to ride in Singapore from May 27 to June 17, part of her prize for being dux of the South Australian Apprentice Academy.

Although it will temporarily interrupt her bid for the Adelaide jockeys' premiership, she said it was an easy decision to make.

"I think every jockey aspires to go overseas and try something different and I think I'm at that stage in my career where I'm ready to do so," she said.

"It has come at a bit of an awkward time but it's an opportunity I can't give up.

"I just hope that when I get back the winners keep rolling in and I can secure the premiership."

Clark leads the Adelaide metropolitan premiership with 42 wins, two clear Jamie Kah, who is now based in Melbourne, and nine ahead of Jason Holder.

She has an unbeatable lead on the South Australian statewide premiership with 120 wins, 40 more than Todd Pannell.

Clark said the chance to ride in Singapore would cap an exciting month, after competing in multiple group races over the Adelaide carnival.

She won the listed Nitschke Stakes on East Indiaman before finishing third on the same horse in the listed Adelaide Guineas and on Saturday she was a close second on Hinchpin in the group 3 Sires Produce.

Clark believes the tempo of Singapore racing will suit her.

"They're fast-paced races and I cant wait to ride some different horses and compete against different jockeys - the way they ride suits my style," she said.

"Hopefully, it can only improve me."

Master Longford trainer David Crosswell added to his big collection of feature races when Highland Vintage just held on to win the Tasmanian Country Derby final in Devonport on Tuesday.

After leading clearly to the home turn, Highland Vintage ($4.80 to $5.50) came under siege as Atley Quick railed through to challenge then runner-up Buckle Up Rhonan ($26 to $18) made a late dive between them.

Highland Vintage got the photo by a half head .

Burnie trainer Allan Clark produced an upset winner of the Tasmanian Country Oaks final with the longest-priced runner in the field, Lady Danger, leading virtually all the way.

Lady Danger was friendless in the tab.com.au fixed-odds market, drifting from $26 to $41.