Growing up in a racing family, horses have always been part of John Thompson's life but he clearly remembers the first race to make an impact on him.

It was the 1983 Golden Slipper and Been There, trained by his father Vic Thompson, finished second to the great Sir Dapper.

Almost 40 years later, the next generation trainer is preparing to saddle up his first runner in the two-year-old dash in Skyline Stakes winner Mamaragan.

"I reckon Been There, when he ran second, was the first race I can ever remember watching," Thompson said.

"There was a bit of excitement in the family and I remember being at home watching it. I didn't go, I was only young, but that's the first race I can ever remember."

Vic Thompson, himself the son of accomplished trainer Vic Thompson senior, never won a Golden Slipper, although he notched another placing with Boasting in 1987.

If John Thompson is to better his father's record at Rosehill on Saturday, he will need to defy history.

Mamaragan will attempt to become the first horse to win the Golden Slipper (1200m) at just its second start, after making a winning debut in the Skyline Stakes on February 29.

He will also become the first youngster to make its debut so close to the feature and win.

Toy Show currently holds both records, racing for the first time 31 days before the Slipper and going into it with two runs under her belt.

Mamaragan's unorthodox preparation has been by necessity rather than design but Thompson cannot fault the colt.

"We just played the cards we were dealt. That was when he was ready to run when he won the Skyline and being his first start, I didn't want to run him again and then back him up into a Slipper," Thompson said.

"I thought, I'll just go straight to the Slipper and if he's good enough, he's good enough."

Mamaragan had his first look at Rosehill last Saturday when Thompson took him for a day out, galloping him between races with stablemate Dreamforce, who lines up in the George Ryder Stakes (1500m).

The Wandjina colt has drawn the inside gate in the Slipper and Thompson says that could be crucial.

"For an inexperienced horse it was good to draw the fence. It gives him something to follow," Thompson said.

"If you watch his race the other day, when he was outside the leader he was a little bit new but when he beat it off and went to the fence it gave him confidence and he ran away from them a bit."

Mamaragan was a $16 chance with TAB on Friday with Farnan holding favouritism at $4.80, just ahead of Blue Diamond Stakes winner Tagaloa ($5).