In-form jockey Glen Boss has sent a clear warning shot to his rivals that he is out to make up for last spring's disaster.

Boss snared his second straight treble at a Saturday metropolitan meeting when he steered home three winners at Caulfield.

He also claimed a hat-trick at Moonee Valley last Saturday.

Last year - almost 12 months to the day - Boss injured his shoulder when his mount, Crystal Lily, dropped dead underneath him during a barrier trial at Flemington.

The triple Melbourne Cup winner was sidelined for the entire spring carnival as he recovered.

But on Saturday Boss confirmed he was back and full of optimism.

The big occasion rider proved he was back to his peak as Melbourne's majors got underway with three strong victories and an air of confidence.

Boss said his shoulder had completely recovered and he had worked hard during the winter to ensure he returned for the big races without any issues.

"My body feels good, my shoulder feels great and it's spring time - I just fire up, I just love it," Boss said after kicking home Detours in the Group Three Sportingbet Sprint (1200m).

Boss began his winning run with a length victory aboard Hvasstan in the Le Pine Funerals Handicap (1700m).

He saluted the judge again aboard Ocean Park in the feature race, the Underwood Stakes (1800m) - the first Group One race of the Melbourne spring.

Boss guided Ocean Park to a half length victory over Voila Ici as Peter Moody's heavily-backed favourite Manighar flopped to finish sixth.

Boss said he had ridden relentlessly during the winter to return to full match fitness.

"I've just made a real concerted effort to go to as many race meetings as I could," he said.

"I think I rode 15 days straight through the winter one time."

Glamour mare Mosheen, meanwhile, produced a reassuring effort to finish fifth in the Sportingbet Sprint.

She underwent a minor throat operation last month and returned with a lacklustre first-up performance at Flemington.

But Saturday's effort prompted trainer Robert Smerdon to confirm that she would back up in next Sunday's Group One Sir Rupert Clarke Stakes (1400m) at Caulfield.