Mike Moroney is still learning about lightly raced English import Buffalo River but the trainer is hoping the free-running gelding can make it two wins from as many Australian starts at Sandown.

Buffalo River scored a front-running win in benchmark 70 grade at Ballarat on May 22 and Moroney has opted to keep him at 1400m for Saturday's Ladbrokes Multiverse Handicap against his fellow three-year-olds.

"We didn't quite know what to expect first-up here but it was a good win," Moroney said.

"He had reasonable form around some nice horses as a two-year-old in England so we knew he had some ability but he's not the most straightforward horse to train so we were guessing a little bit."

Moroney said he knew Buffalo River was a free-rolling horse when he came to him from John Gosden and does not see that changing.

"We thought that if we gelded him and got him to relax a bit that he might change," he said.

"But no matter what we've done, he's better if he does free-roll a little bit.

"He's just one of those horses who looks to me as though he's got a high cruising speed and is going to get a mile (1600m) or mile-and-a-quarter later on.

"Just with the speed he has shown we thought we'd stay at the 1400 metres on Saturday and we're really still just learning about the horse."

Moroney has spring aspirations for another import, five-year-old Mr Marathon Man, a Listed winner in France, who runs in a heat of the Winter Championship Series on Saturday over 1600m from the outside barrier.

Mr Marathon Man was unplaced in the Wangoom Handicap (1200m) at his Australian debut before a fourth to Spanner Head over 1400m at Flemington last month.

He will wear ear muffs during the race this time, with Moroney trying to get him to settle better than he did at Flemington when he over--raced.

"We've waited for this race and we've given him a jump-out in between," he said.

"We really want to get him through to the spring so that's why we don't mind spacing his races out at this stage.

"He's also not the easiest horse and we're finding our way with him a bit too. He was going to relax nicely enough at Flemington last start and then he got a bump and it fired him up and he over-raced from there.

"We think a fair bit of him, so he's good enough to be around in the spring."