Apprentice Chad Schofield scored the biggest win of his career aboard Gregers in Saturday's Group Two Thousand Guineas Prelude.

And the young rider already has his eyes on an even bigger prize with the David Hayes-trained filly in the Group One Thousand Guineas next month.

Gregers ($6.50) confirmed her claims as a serious Guineas contender, racing to a long head win in the 1400m fillies feature after Schofield was forced to cut the corner on the inside as the field fanned wide looking for better ground.

She sprinted quickly to hit the front closest to the inside and was strong to the line to defeat Marianne ($8) with favourite Politeness ($3.10) another half length away third.

The victory on Gregers was 19-year-old Schofield's first at Group level and also redeemed him after Hayes was critical of one of his earlier rides on the card aboard Great Esteem.

"As long as you can bounce back that's very important," Hayes said, praising Schofield's winning ride.

Gregers had been favourite for next month's Thousand Guineas after two wins last month but has since relinquished that position which is held by star Sydney filly Guelph who impressed again in winning Saturday's Tea Rose Stakes at Randwick.

"Guelph is very good. She might be better in Sydney, I hope," Hayes said.

"This filly (Gregers) is going to be pretty hard to beat in anything she runs in. When things go her way I think she'll be devastating."

Hayes said Gregers was likely to go into the Thousand Guineas (1600m) on October 16 without another run.

Schofield, last season's champion Melbourne apprentice, was thrilled to bring up his first Group win on a filly he said was close to his heart.

"I had no option but to come back to the inside on the worst part of the track, and I thought the best filly won on the day," Schofield said.

Schofield initially had his concerns Gregers might not settle enough for the Thousand Guineas distance but after her past two starts he is confident she'll have no problems.

"I think she might even have a better turn of foot over the mile and who knows what can happen," he said.