Andrew Pieper wouldn't have minded if the ground opened up and swallowed him at Rosehill on Tuesday after he drew the unlucky barrier 13 for She Will Reign.

But on a damp Saturday afternoon on Golden Slipper Day, Pieper was walking on air after watching the cheapest horse in the world's richest race for two-year-old's romp home on a heavy 10.

"I'm not sure what to say. We've won the Golden Slipper and words can't describe how good it feels. I still can't believe it," he said, amid joyous scenes.

Pieper was also stunned when he drew No.13, the gate that has propelled zero winners to glory since the Slipper was first run in 1957.

Fortunately She Will Reign and jockey Ben Melham ended up jumping from barrier 11 when the two emergencies draw inside her didn't get a run.

One of 19 mostly first-time owners, Pieper can now reflect on his own inspired decision to purchase a share in the $20,000 yearling.

"It was a phenomenal ride and (trainer) Gary (Portelli) has obviously got the horse fit," he said.

Although She Will Reign scored by 2-1/4 lengths, Pieper took nothing for granted in the dying stages.

"I knew we'd won at the post. You can't claim it till it runs past."

Pieper heads back to Tamworth on Sunday and looks forward to viewing the race dispassionately.

"Someone would have taped it. I'll watch it a hundred times."