Harry Coffey's third city double in the past month has boosted his chances of winning this season's Melbourne apprentices' premiership.

Coffey notched his 20th Melbourne city winner for the season when he brought up his double at Caulfield on Monday on the Darren Weir-trained Tooleybuc Kid in the Mistable Handicap (2000m).

He had earlier guided stablemate Princess Hussy to a maiden win in the opening race.

"He's a great kid and deserves everything he gets," Weir said.

"He works hard at it and he's from a good family."

Coffey moved to outright second on the Melbourne apprentices' premiership, only three wins behind the sidelined Patrick Moloney who will be out for much of the remainder of the season with ankle injuries suffered in a race fall earlier this month.

Weir's double took him 17 wins clear of Peter Moody on the trainers' table.