Lee Magorrian was in no mood to celebrate after Mortar Platoon clung on to record the Irish apprentice's first Saturday double at Randwick.

Not only had the effects of getting his weight down to 54kg tempered Magorrian's excitement, he also has to work some of Chris Waller's team at the beach on Sunday morning.

"I'm dry retching here boys, I'm a bit sick through wasting," Magorrian said.

Mortar Platoon ($31) withstood a late challenge out wide from $3.60 favourite Impavido to claim a Benchmark 85 Handicap (1600m) by half a neck.

The gelding's third win of his 16-start career complemented Magorrian's win aboard the Gary Portelli-trained Improvement in a Benchmark 85 Handicap (1400m).

Magorrian, from Trim in County Meath, also had a win midweek at Canterbury so the diet set by Waller's staff has been worthwhile.

"It's tough. I'm not one of the smallest jockeys around but I'm reaping the rewards," he said.

"Everything's been going well, the preparation for race day has been going good. I'm in a better head space and riding better."

Waller's racing manager Charlie Duckworth praised Magorrian, who is attached to the stable until the end of the season.

"It's absolutely super for Lee, finally all of his work is paying off."

Magorrian was assured by Waller and Duckworth that Mortar Platoon would be worth the sacrifice.

"They're pretty good judges. Once he hit the front he idled a bit and I had to get get pretty stuck into him then he really put the head down and charged."