Maureen Haggas told Racing TV viewers on Wednesday night that the ride Zac Purton gave the stable's Lake Forest in Australia on Saturday was "about the worst I think I've ever seen in my entire life".
Lake Forest was a well-fancied 17-5 chance for the Group One King Charles III Stakes at Randwick, a race with a first prize of almost £1.46 million.
But the four-year-old was slow away under Purton, a multiple champion jockey in Hong Kong, and was never a factor. The combination trailed home last of the 12 runners.
Racing TV's Anthony Dunkley spoke to Haggas at Kempton on Wednesday evening after she had saddled
Zennor Storm to success.
Watch what Maureen Haggas had to say to Anthony Dunkley
He asked how the stable's Australian runners had taken their exertions and the daughter of the legendary Lester Piggott gave a blunt appraisal of Purton's efforts, suggesting he sat like a "big Sissy".
"As far as I'm concerned, Lake Forest never had a race," she said. "It was about the worst ride I think I've ever seen in my entire life.
"I was appalled, absolutely appalled. We went all that way and, I mean I don't know Zac Purton at all, but it was just dreadful.
"It was so disappointing because everyone knows he is a horse that you have to tell what to do. He knew that, and he was told it, and he just sat there like a big sissy."
Haggas added: "I was horrified, I really was. We've gone all that way at huge expense on the owners' part and it just makes you realise how lucky we are with the jockeys we have in England, Ireland and France when you compare them to the rides we got on Saturday which were, as I say, really shockingly awful."
Purton says Lake Forest gave him "no response"
On the same card at Randwick, Purton steered star sprinter Ka Ying Rising to more glory in The Everest and, on Wednesday, he celebrated riding his 1900th winner in Hong Kong.
He shared his thoughts on SENTrack's Giddy Up show overnight, saying: "I didn't speak to her [Maureen Haggas] after the race. She and Willie weren't down there – obviously they watched it from up there.
"She's got her opinion, which she's entitled to. I thank her for her advice but I haven't had time to watch the replay yet because I've been too busy watching replays of myself winning the $20 million Everest.
"I followed Ceolwulf who went on to win the race and thought he's not too bad a horse to follow and he put seven lengths on me. As soon as they quickened my horse just went up and down on the one spot.
"He gave me no response at all. I'm a little bit bemused at her take on the race, but she's entitled to that, no problem."