"She always worries me because she likes to have horses around her and I was at her a fair way from home to keep her mind on the job," Harpley said.
"Once she could sense Priceless Gem was on her outside she switched on and the best she felt during the entire race on Saturday night was in the last twenty metres."
Harpley will not start his star mare this weekend believing she has done enough to be at her peak.
"She has had to do a fair bit of work in the runs she has had this season, she hasn't really had a soft run yet plus I gave her a good hit-out at the Wagga trials last weekend so I'm pretty confident that she will be as good as I can get her in the Breeders Challenge final."
While the barriers for the semi-finals were drawn using a preferential system, the final will be random.
"I think that is the best way to do it, a lot of the lower class mares may not nominate for the semi finals if they were a chance of drawing the outside but I like the idea of it being random once the final comes around."
"Thetrained mare Grin For Miss was impressive in the other semi and she does possess some gate speed so if she drew underneath me it would be a good race for the early lead and Priceless Gem was very good in finishing second behind Frith last week too."
Frith will be attempting to win her second Breeders Challenge after winning it last year as a three year old filly.
By Greg Hayes (Harness Racing NSW)