Stewards wasted no time in upholding a protest after promising filly Kaizaen was beaten by the barest margin at Caulfield on Saturday.

Jockey Craig Williams fired in an objection against Glyn Schofield's mount Amicus, saying the Sydney filly had denied him a straight run to the line in the Cove Hotel Handicap.

Williams said Schofield's whip also made contact with the head of Kaizaen when the two fillies were racing close together over the final 200m.

He also told stewards Amicus had shifted out in the straight taking him off course which was enough to cost him the win.

"The margin is the shortest of margins, so even if he has just run me off course I still would have beaten him," Williams said.

Schofield insisted Amicus always had Kaizaen's measure and would have kept fighting her off.

Trainer Robert Smerdon has a good opinion of Kaizaen who was having her third start and has Oaks plans for the filly.

"We've taken the view that we're going to give her the chance in better fillies races," Smerdon said.

"I'd like to think a filly with her physique and racing style might make an Oaks filly."