A bigger and stronger Houtzen has fought off her challengers to win the Group Three PJ Bell Stakes and shake the tag of being purely a speed machine.

As a two-year-old, Houtzen had a reputation as a catch-me-if-you-can filly but trainer Toby Edmonds said that was mostly because of wide barriers, including in the $2 million Magic Millions Classic in which she led all the way from the outside gate.

On Saturday at Randwick with Glyn Schofield aboard, Houtzen ($8.50) was able to take a sit off Dinnigan and Debonairly.

As the fillies geared up for the run home, Houtzen took the lead inside the 200m and showed her strength to kick back and put a short neck on Manicure ($21) and Problem Solver ($15), who could not be separated for second.

"I'm both relieved and elated," Edmonds said.

"There were some doubts whether she was the genuine type being such a precocious two-year-old.

"We knew we had her quite underdone coming here a month ago when she ran third.

"She's a much bigger and stronger filly now. She is turning into a mare.

"Depending on how she comes through this race we could back her up next week in the Arrowfield Sprint."

The $500,000 Group Two Arrowfield Sprint (1200m) is open to all three-year-olds.

Schofield, who rode Houtzen in the Listed Fireball Stakes (1100m) on March 3, said she had improved in those few weeks.

"The credit goes to Toby because he told me she would take a bit of improvement from her first run and he was spot-on," he said.

"She was very brave, the pace was very very strong she stalked it and took over like she was going to win easily.

"When she got challenged I felt she was going to give up but in the back of my mind she reminded me of what she did last time when she fought strongly."

Damien Oliver, who rode the $3.50 favourite She's So High, who finished fifth, said he thought the Mick Price-trained filly was going to win.

"I was happy enough with the run," he said.

"When I pulled out at the top of the straight I expected her to run over the top of them but they just kept running off the front so it made it a bit difficult to make ground."