The Victoria Derby barrier draw will be crucial if So Si Bon is to turn the tables on Sacred Elixir when they meet again in the Classic at Flemington.

That's the opinion of So Si Bon's trainer Robbie Laing who is confident the colt only needs a little luck on Saturday.

So Si Bon is the Derby $7 second elect after his third behind the New Zealander in the Vase on a soft Moonee Valley track last Saturday when Sacred Elixir stamped his $3.20 favouritism.

"If I draw gate one and Sacred Elixir draws 18, I'm a good chance of beating him and if Sacred Elixir draws one and we draw 18 then I'm a remote chance," Laing said.

Laing thought his Derby hopes were dashed when So Si Bon was under pressure before the turn in the Vase (2040m) and appeared to be struggling.

"On the corner he was starting to skate because he can't handle rain-affected ground and they got up on his inside and came around him and I thought he was going to run eighth," Laing said.

"I was thinking what am I going to do, do I keep going to the Derby but then he got going again.

"He's come through the run well so it's on to the Derby."

Laing said So Si Bon spent 30 minutes on an aquasizer on Monday afternoon and worked over two laps at Cranbourne on Tuesday morning.

Hugh Bowman, who teamed with Laing to win the 2013 Derby with Polanski, will ride So Si Bon and will get to know him in a work-out on Thursday morning.

Laing didn't consider So Si Bon a Derby colt early in his preparation, with the trainer's sights set a little lower towards races like the Carbine Club Stakes and Sandown Guineas.

"He's only 15.2 (hands) and 490 kilos but importantly he's got an engine," Laing said.

"He's been getting back but relaxes and hits the line hard so we thought we'd try the Derby."

Bowman will also will also ride the Laing-trained Missrock in Saturday's Wakeful Stakes, the tradtional Oaks lead-up.

The Derby barriers will be determined on Wednesday.