"I really wanted to run her in a mile race. Everybody was keen to see how she would go over a mile, including myself, but I really doubted that she'd run it," Sadler said.
"She was given a beautiful ride and every chance to run it, but I was surprised how strong she was at the end of it.
"She ran right through the line and that's probably her best win.
After winning four of seven starts last time in, finishing runner up on the other three occasions, Sadler said there had been a few little factors against Merrigold this campaign that were rectified on Saturday.
"I suppose last campaign, she had seven runs, she won four, and ran second three times and had a terrific campaign.
"This time, she hasn't won a race this time until today.
"Her only bad run was on a very wet track which she doesn't handle at all, and the rest of her runs have been somewhat unlucky,