Matthew Williams has had St Joeys earmarked as a horse of promise for some time and the Warrnambool trainer will get a better gauge on his ability when he makes his city debut at Flemington.

St Joeys raced once in his first preparation as a late two-year-old in June, finishing fourth in a 975m Swan Hill maiden.

He returned from a spell with a 4-1/-2-length maiden win on his home track over 1200m on December 1.

He makes his first city appearance in Saturday's December Twilight Handicap for three-year-olds over 1400m.

"He's a horse that we've really liked for quite a while," Williams said.

"He'd shown us quite a bit going towards Swan Hill and I thought his run over an unsuitable trip was really good.

"We gave him a good break and let him mature out a bit more.

"He's come back and he's a lovely big, strong horse who is well-developed, lovely and sound, and he's got a great little turn of foot on him.

"He's always shown a bit on the track and in his trials."

Williams said St Joeys put the race away quickly at Warrnambool and he believes the step up to 1400m will suit.

"With the horses we've worked him with at home, older horses rated around that benchmark 80, he matches strides with them and gives the impression for this off-season three-year-old racing he should be able to measure up and make the grade," he said.

Williams said he harboured hopes St Joeys could progress to a Derby in South Australia or Queensland later in the season.

"Obviously he's got to take the next step first on Saturday," he said.

"And there's been a little bit of interest from Hong Kong for him after his win at Warrnambool so that would probably only strengthen as well if he was to run top three on Saturday in town."