Tests have revealed that Sagitta 1,000 Guineas favourite Petrushka was not in season when only third on Sunday but connections are no nearer to knowing the cause of her below-par showing.

Connections had put that forward as a possible explanation for her run, in which she was uncharacteristically off the bridle throughout the race, before staying on to grab minor honours.

But Harry Herbert, manager of owners Highclere Thoroughbred Racing, confirmed yesterday: "All we know is that it would appear she was not in season. There is no real explanation and I'm not sure that anything will come to light now. But she will now definitely go for the Oaks."