Because of COVID-19 restrictions, trainer Matt Cumani and his staff have had a subdued celebration after Khoekhoe gave the stable its biggest success.

But they might let their hair down if either Sign Seal Deliver or Tarn's Prince can follow Khoekhoe's win in the $800,000 The Showdown at Caulfield last week by taking out the Listed VRC St Leger at Flemington (2800m) on Saturday.

"For me to win a sharp 1200 metre two-year-old race one weekend and a staying three-year-old race the next would really be the icing on the cake," Cumani said.

"They are very much St Leger style horses and suggest they want this type of distance.

"But none of these stakes races are ever easy.

"I think it's a mistake to think you purely need a stayer and it doesn't matter what quality, as at the end of the day they still need to be quite good."

Saturday's race is one of Australia's oldest, pre-dating the Melbourne Cup, and is the only St Leger still run in Australia for three-year-olds.

Sign Seal Deliver, a $200,000 yearling, is part-owned by Cumani's father Luca, a successful UK trainer who retired in 2018.

Cumani said his mother Sara and sister Francesca along with his father were all involved in buying Sign Seal Deliver at the Magic Millions sale.

"My sister and mother would go off in one direction, my father and I in another and we had our bloodstock agent as well," Cumani said.

"It worked well. We covered all the horses and this was one everyone liked.

"He was an absolute stunner, a very attractive horse."

Sign Seal Deliver broke through with a Sale maiden victory at start No.8 on April 14.

In his first campaign, Sign Seal Deliver progressed to the Victoria Derby (2500m) at Flemington last spring at his fourth start after which he was gelded.

"We're hoping he will become a really nice, tough campaigner over many seasons to come," Cumani said.

Cumani was impressed with the effort of Tarn's Prince to finish fifth behind fellow St Leger contender Royal Crown over 2400m at Caulfield on April 11.

"He's a different type to the other horse, not a particularly attractive horse, but he's big and strong and rangy," Cumani said.

"He's hopefully got that ability of having a lot of stamina and also some speed which he gets from his sire."