After going winless in two metropolitan meetings this week, apprentice Beau Mertens needs to hit back at Moonee Valley after being joined in the Melbourne jockeys' premiership lead.

Mertens and premiership rival Craig Williams both failed to ride a winner at Monday's Mornington metropolitan meeting before Williams joined his younger rival in the lead with a winning double at Sandown on Wednesday.

There are 12 city meetings remaining as Williams chases a sixth premiership while Mertens strives to become the first apprentice since Nick Ryan in 2004/05 to snare the title.

Both have full books of rides on Saturday's nine-race Moonee Valley program with Mertens' chances including If Not Now When and Leodoro who are early favourites for their respective races.

Williams also has a quality book including early favourites Miss Vista and Hursley.

At the most recent Moonee Valley meeting two weeks ago the pair rode the first five winners between them, with Williams getting a treble and Mertens a double.

Williams is no stranger to battling out a title race and while there is a new challenger this time, he remains highly motivated.

"It's 12 months work and I really want it badly, and so does he, so it's great," Williams said.

"He's encouraging me to ride better all the time."

Williams has put off holiday plans until the end of the season as he settles in for another title push.

"He's riding really well and the pressure hasn't got to him and it's great competition," Williams said.

"I hope everyone else is enjoying it because Beau and I are driving each other to get the best out of each other."