John Sadler praised the ride of apprentice Patrick Moloney as Marli Magic raced to a city win at Moonee Valley on Saturday.

And Sadler said it was a thrill for him to see Moloney partner the mare to victory, highlighting a long connection between the two families.

"My mother, who is actually here today, she's 107 and she played piano for Patrick's grandfather's wedding," Sadler said.

Moloney hails from a famous racing family, with his grandfather Jim the man who prepared champion sprinter Vain.

Marli Magic, the $3.70 favourite, had the inside barrier in Saturday's 1600m benchmark race for fillies and mares but Sadler was keen for Moloney to find a position one off the fence if possible.

After beginning well, Moloney was able to find a spot just behind the lead and one off the fence before the mare hit the front in the straight.

Arena Rock ($4.20), chasing her third straight win, challenged on the outside but in the end a 6kg difference in weights was the telling factor as Marli Magic held on to score by a short neck with 1-1/4 lengths to Hot Ruby ($12) third.

"The second horse did a big job under the circumstances," Sadler admitted.

"But Marli Magic was well ridden. We asked him to do that if he could but it was a bit of an ask from barrier one.

"He had it done within the first 100 metres and it was a really good effort.

"I've given him (Moloney) quite a few rides and he hasn't had a lot of luck but it was only a matter of time."

Marli Magic notched the fourth win of her career and her first on a city track.