A week after returning to the Sydney riding ranks from Hong Kong, Christian Reith has claimed a welcome win aboard the Gai Waterhouse-trained two-year-old Giulietta.

The debut win has qualified the filly for a Magic Millions start but Waterhouse's representative Mark Newnham says she will not back up in the $2 million race at the Gold Coast next week.

Giulietta, the $4.40 favourite, showed professionalism beyond her experience to lead all the way, beating I'm Not Sure ($7.50) by 2-1/2 lengths with My Colleague ($31) a nose third.

Reith, who spent much of 2014 in Hong Kong, admitted that although he had enjoyed the experience, he was glad to be home.

"Hong Kong taught me to appreciate home more," Reith said.

"We only rode twice a week and I was climbing the walls. Now that I'm back I'm riding trackwork everywhere and hopefully I can spread myself around.

"It's great to be able to ride a filly like this. She has a beautiful action with speed early and speed late.

"She is still learning and is a very nice filly on the way up and can only improve again."

Although Waterhouse had indicated Giulietta would run in the Magic Millions if she won on Saturday, Newnham said immediately after the race the trainer has sent him a text ruling it out.