Apprentice Beau Mertens remains positive ahead of the next instalment at Flemington in his bid to claim the Melbourne jockeys' premiership.

Mertens endured a frustrating day at Sandown on Wednesday where he had seven rides without a winner, finishing the meeting with five second placings and two thirds.

It wasn't the result he was hoping for and with Craig Williams drawing level in the premiership race, Mertens knows he's in for a battle.

"I can't complain," Mertens said.

"Seven placings is better than seven lasts.

"All my horses ran well and hopefully next start I can get back on them and win.

"It was a super pay day but it doesn't help the scoreboard at all as placings aren't really a key factor this close to the finish of the season.

"We can go into Saturday with a clear mind knowing that I'm riding well."

With three meetings left in the premiership race, Williams has tightened his grip on favouritism as the $1.50 top pick with Mertens drifting from $2.35 to $2.60.

Mertens has six rides on Saturday and only three of them are rated in single figures but Kilimanjaro is the $3.10 favourite in the George Watson Handicap.

On the other hand Williams has rides in eight of the nine races, with all mounts under double figures including five pre-post favourites.

Mertens admits he could have lost a few of the higher-weighted horses he may have ridden to other apprentices since losing his claim following a winning treble at Flemington on July 8.

But he says he is still getting good support from regular clients.

"Not much has changed since I lost my claim," he said.

"I'm still getting the quantity but probably the quality has dropped off a bit.

"I've just got to keep working hard and hopefully they'll came back."