Unbeaten South Australian three-year-old Lord Aspen faces his acid test when he lines up in the Sandown Guineas.

The winner of four races, Lord Aspen graduated from restricted grade in Adelaide to success at Listed level at Flemington last week.

On Saturday he rises to Group Two company and goes to 1600 metres for the first time but Murray Bridge trainer Mick Huxtable believes he is up for the challenge.

"This is no doubt his acid test," Huxtable said.

"I've said before that if everything fell into place we'd end up here, and here we are."

Lord Aspen enjoyed a cosy run under Matthew Neilson at Flemington before "coasting" when he hit the front.

Huxtable says he believes Lord Aspen has improved since his win last week and the gelding has enjoyed a light few days.

"He's super, very well," Huxtable said.

"I think he's come on since last week, but he'd need to also.

"He's tightened up that little bit and looks beautiful."

With a nice draw in barrier six in the 13 horse field, Huxtable said he can see Lord Aspen racing in fourth or fifth position, similar to where he was positioned last week.

But he will be instructing Neilson to wait as long as possible before pressing the go button on the long uphill run at Sandown.

"From the barrier hopefully he'll be running fourth or fifth," Huxtable said.

"But at Sandown that last little bit finds you out if you get there too early, so Matthew will have to be careful with that."

If successful, Lord Aspen will be the second Murray Bridge-trained galloper to win the Sandown Guineas this century after Pay Keys was successful for John Hickmott in 2003.

Pay Keys had also been successful at Flemington in the lead-up, winning over 1800m on VRC Oaks Day before coming back in distance.