Knee problems have restricted the career of Emmalene but trainer Liam Birchley is confident she is poised to return to black type success at Randwick on Saturday.

The mare's patient owners include rugby league greats Ricky Stuart and Laurie Daley.

Emmalene won at Listed level at Flemington during the 2011 Melbourne Cup carnival at only her fourth start, prompting Birchley to rate her among the best horses he had trained.

But the daughter of Jet Spur lost form during an autumn and winter carnival campaign last year before bone chips were discovered after she finished 11th in the Tatt's Tiara at Eagle Farm.

"Looking back on it now I think it might have been brewing for a while and a spur or something broke off on the near side after her last run during the winter," Birchley said.

The mare vindicated Birchley's long-held faith when she won impressively at Eagle Farm on March 30 when she resumed from a spell.

That victory has convinced Birchley she is going well enough to tackle Saturday's Group Two Sapphire Stakes (1200m) at Randwick with Damian Browne booked to ride.

"I'm really happy with the way she came through her first-up win and now that she's fully matured I'd like to think she can go on with it," he said.

While Birchley feels Emmalene's knee problems were the primary cause for her form slump last campaign, he believes there were other contributing factors.

"A couple of times she drew shocking gates and had to go right back to near last in the run and she did a lot better than it looked at first glance," he said.

Plans for Emmalene beyond the Sapphire aren't set in stone but Birchley is likely to again aim the mare at the Group One Tatt's Tiara (1400m) at Eagle Farm in June.

Birchley's Magic Millions placegetter Missy Longstocking is back in work at Eagle Farm and will be ready to trial on Tuesday week at Doomben.