He said: "Today was a real good blow out, she's a lovely big strong mare. She's got a great gait, she's fit and very sharp.
"If anything she could be a little too sharp maybe the distance might be a query.
"You've just got to be mindful of the draw for her that's the main thing.
"I think if she can draw a low gate she'll see the trip out. If she draws wide and she has to do a bit of work, I fear that may drag it out of her."
Murtagh partnered Septimus in his final workout also at Sandown and trainer Aidan O'Brien was happy to see the five-year-old gallop past stablemates Honolulu and Alessandro Volta at the end of a 1,200 metre spin.
He said: "Johnny was just going to get him relaxed in behind. They were rolling to the furlong, then he lengthened without being asked too aggressively. We were very happy with that."
Murtagh added: "He finished off nicely. I hope I draw between seven and 15. He's a straightforward horse."
