Bush trainer John Matheson's only galloper in work, Jittery Jack, made it successive city wins when he relished the heavy conditions to thump his Moonee Valley rivals by seven lengths.

Jittery Jack ploughed through the ground to win the 1600 metre event in what would prove to be the final race on the program before it was abandoned due to safety concerns over the track.

Apprentice Liam Riordan, who was also successful on Jittery Jack at Flemington at his previous start, had a pre-race plan to take him to the front from the outset as horses weren't making ground.

Riordan enacted his plan to a tee, but Matheson admitted he wondered whether the young rider was over-doing it and was concerned he was too far in front too early.

It didn't matter as the further the race went, the greater the margin became between Jittery Jack and his rivals.

"We were a bit nervous when he got so far in front because we were worried that, at the first time at the mile, he might start and stop in these conditions," Matheson said.

"We knew he'd relish the conditions but it was just the distance that we were worrying about."

Riordan said he wanted to play catch-me-if-you-can with his rivals from the outset.

"I made sure I used my barrier and gave him a good dig and then ran along the whole way," Riordan said.

"I was going quite quickly but I was quite confident that into the head-breeze and the heavy track, it was quite hard for horses to make ground. I'm just glad we pulled it off."

Jittery Jack's time of 1:44.76 for the 1600m was the second slowest recorded at Moonee Valley in 600 races run over the distance since 2007, according to Racing.Com.

Jittery Jack ($5.50) defeated No Change ($5) by seven lengths with Irish Flame ($10) a further six lengths away third.