The Boels-Dolmans rider crossed the finishing line in Douglas, Isle of Man, more than 100 metres ahead of Katie Archibald (Team WNT) and Hannah Barnes (Canyon-SRAM).
The result, however, was far from convincing: on the chase up Snaefell Mountain, Olympic team pursuit champion Elinor Barker (Matrix) jumped off the front and eventually built a solo lead that hovered around 40 seconds, an advantage that had thinned out to 17 seconds with just one seven kilometre lap left.
Deignan had been part of a larger group containing nine riders at one point and wary that no one would work with her, she knew she had to instigate the chase herself to stand any chance of victory, and thus the chase was reduced to three.
“I knew once I had a group of three, they would work collectively and would commit to it,” Deignan told Cycling Weekly. “Where there was 12 of us, people would do a turn and then stop.
“But when there was three of us going for a medal, we worked together and closed the gap. I wanted to work as a proper group and get to the finish, but everyone was looking out for themselves which was understandable.
“I made the decision to make it a smaller group of three.”
With Deignan – who was being cheered on by her grandparents and Team Sky husband Philip who is not racing in the Irish National Championships – reeling in Barker togehter with Barnes and Archibald, she was cautious that the former, the defending champion, possessed a sprint that could match hers.
“I didn’t want to take it to a sprint,” Deignan added. “I knew once I took Hannah and Katie with me I’d have to get rid of them.
“That kicker with two kilometres to go, I used that in each of the last three laps, just to take the sting out of everyone.”