The Welsh Grand National at Chepstow is likely to be the next target for Ms Parfois, after her fitness booster in Saturday's Ladbrokes Trophy.
The talented mare was well fancied for her return in the race formerly known as the Hennessy, and looked to be going well on the final turn, before fading back to sixth up the straight.
Trainer Anthony Honeyball felt she needed the run more than his team had initially thought.
(Credit: Timeform) He said: "It was a solid enough run really. She had good form with the winner (Sizing Tennessee) and the second (Elegant Escape), but that was at the end of the season when she was as fit as a fiddle and she was on her A-game.
"In hindsight she has needed the run at Newbury, and it has found her out really. There is nothing we could have done," he said.
Under Honeyball's guidance, she enjoyed an excellent campaign over fences last season as a novice, landing back-to-back Listed contests at both Newbury and Warwick.
She then found one too good three times in a row, when finishing second to Black Corton at Ascot in the Reynoldstown, runner-up at Cheltenham in the four-mile behind Rathvinden, and at Aintree in the Mildmay Novices' Chase, where she was three lengths down on Terrefort.
Honeyball hopes Ms Parfois can raise her game for the Chepstow marathon over the Christmas period.
(Credit: Timeform) He added: "There was a lot of promise for the run, and she has probably never gone that quick over the first few fences in her life. We went there meaning business, but if you look at her she was probably carrying a bit more condition than when she signed off last season.
"We will check her out this week - not because I think there is something wrong with her, but when they have a hard race like that you just want to check it hasn't hit her really hard.
"I'm sure she will come out fighting, and if she says she wants to run, we will let her take her chance at Chepstow on December 27th."