Illness forced apprentice Beau Mertens out of a midweek city meeting but he has kept up his title challenge by returning to his winning ways at Caulfield.

Mertens missed Wednesday's Sandown meeting but was back in action on Saturday and notched his 52nd city winner for the season aboard the Henry Dwyer-trained Snitty Kitty in the Changing Places Real Estate Handicap (1100m).

Mertens is a clear leader in this season's Melbourne apprentices' title race and is second in the senior jockeys' premiership, starting Saturday only six wins behind leader Craig Williams.

"After Tuesday I got the flu and it knocked me about a bit," Mertens said.

"So the doctor stood me down and got me up feeling better for today."

The speedy Snitty Kitty ($3.30 fav) led in a stable quinella for Dwyer with If Not Now When running home to finish 2-1/4 lengths behind her stablemate, while the Danny O'Brien-trained Merriest was another length away.

Mertens said his original intention was to lead but Snitty Kitty still got the job done.

"She was quite impressive," Mertens said.

"Obviously plan B came about and I had to sit outside something but I think in hindsight she actually went to the line a bit better.

"She had to chase the horse down in the lead and then when she got to the front she didn't take her mind off the job and hit the line quite well."