Literally seconds before the field reached Sicilian Secret who was surrounded by officials, Donnelly got her charge up and they moved infield, sending the bunch wide.
Shestherealdeal pinned the ears back and won in a time of 3m 37.9s. Gwendene made the move to the outside and rapidly began to close the distance, but ultimately ran out of room and was beaten by around a third of a length, with Bankcard hanging on for third.
After back-to-back victories for Jay Abernethy, it was Sailesh winning the Cup with Shestherealdeal's owner Adrienne Matthews of Pukekohe, the pair having been successful together in the Cup three years ago.
"I think that might have been Sailesh's third win," Matthews said.
She admitted her heart was in her mouth as the bunch approached the fallen Sicilian Secret.
"You just really hope they get the horse up and everything's was alright. I know Arna, we chat a lot.
"You just hope for all the connections that everything's all right."
Matthews said her winning horse has a few little issues so they are likely to stick to grass track racing.
"She's won a lot of races on grass."
Despite scary moments in the feature and the rain coming on-and-off in the early afternoon, the Wanganui Trotting Club got through their full nine-race card in front of a small crowd.