Zac Lloyd has celebrated his second Group 1 win with a breezy Flight Stakes victory aboard Lady Shenandoah.

Chris Waller lost his top seed for the Flight Stakes on race eve, but it hasn't stopped him from claiming the Group 1 fillies' feature with another richly talented three-year-old in Lady Shenandoah.

Odds-on favourite Autumn Glow was found to be lame on Friday, ruling her out of the race and the spring, with Waller confirming she had already undergone surgery for a bone chip in her knee.

While untimely, the injury to Autumn Glow paved the way for Lady Shenandoah to have her moment in the sun at Randwick on Saturday in a race that wasn't always on her radar.

"She wasn't supposed to be running today," Waller said.

"I had her in the trials yesterday and I didn't really want her to be getting up against Autumn Glow this early in her preparation because I thought she was a Thousand Guineas horse.

"It was a small field and that tempted us to run. Even if Autumn Glow ran, we probably would have been running her.

"She's here and she has got a Group One."

Lady Shenandoah ($3.10) settled midfield for apprentice Zac Lloyd and let down with a brilliant turn of foot in the straight to sprint clear, blitzing her rivals by 3-1/4 lengths, Harlem Queen ($7.50) best of the rest and Snow In May ($2.60 fav) another neck away.

While the Thousand Guineas (1600m) in November was the winner's original goal, connections are unlikely to try to hold her together until then.

"It is a long way to wait. I don't think it would be our normal path," Waller said.

Lloyd was thrilled to pick up the second major of his career after his breakthrough Stradbroke Handicap success on the Bjorn Baker-trained Stefi Magnetica and said he was confident she was the winner a long way out.

"The feeling never gets old. The second is as good as the first," Lloyd said.

"And to do it for Mr Waller, who has given me good opportunities in the past and I haven't quite repaid him, but hopefully that makes up for a couple of the bad rides.

"She travelled like the winner the whole way and I just had to count to five before I let her go, but I don't think it mattered. She's very good."

Sam Clipperton was rapt with the effort of Harlem Queen, who couldn't sprint with Lady Shenandoah but came again on the line.

"The winner dropped her on sprinting but she relished the mile and will relish perhaps even 2000 metres and beyond. Really nice filly going forward," Clipperton said.

Kerrin Mcevoy was satisfied with the effort of Snow In May and felt she would be better again in the autumn..

"The winner just kicked away from us at the top of the lane. She will be better into next preparation as well," McEvoy said.