Golden girl Kathy O'Hara hit the lead in the race for the Sydney apprentices' title when booting home her 15th metropolitan winner at Rosehill.

The 18-year-old got everything out of the Kevin Moses-trained Zinzin to stave off the late charge of Mitchell Bell's mount Blue Booty and win the Merrylands RSL Club Hcp (1400m) to move a win clear of Jay Ford.

Ford graduated to the senior ranks in December and cannot add to his tally.

O'Hara has made an immediate impact since transferring from the bush to Gwenda Markwell's Kembla stables just months ago and nobody is more surprised than her.

"It's been a big shock. I honestly didn't think I'd ride this many winners, I don't think anybody did," O'Hara said.

"There is a lot of pressure and scrutiny in the newspapers and I cop a bit of criticism.

"You can ride ten good races and then there will always be something about your one bad ride.

"But criticism is good you've got to learn from your mistakes and not do it again."

O'Hara leads Bell by three wins after he added to his tally with victory aboard the Bart Cummings-trained Mi Casa earlier in the program and she rates him a serious title threat.

"It's going to be tough. Mitchell keeps riding winners and so does Danny (Langridge) and Joe (Fujii)," O'Hara said.

"They all rode winners here today."

Apprentices rode more than half the Rosehill card with Fujii bagging a double via the Moses-trained Skittles and Tim Martin-prepared Langborghini to take his metropolitan tally to nine.

But it was senior jockey Rod Quinn who came to the fore in the Blacktown Workers Club Hcp (1300m) helping Retail Therapy to a long neck win over a wayward Miss Mooney Mooney.

Starcraft's half-sister and favourite Pin Up threw her chances away at the start before getting home for fourth.

"She fell on her head coming out of the gates," Pin Up's jockey Jamie Innes said.