On only six occasions has a New Zealand flag been raised at an Olympic swim meet - and not since Danyon Loader's golden double 16 years ago - so while the eventual outcome was a disappointment, that came out of a terrific performance to get the opportunity in the first place.
Frenchwoman Camille Muffat won the final in an Olympic record 4:01.45 after a thrilling duel with American Allison Schmitt, while Britain's golden girl, defending Olympic champion Rebecca Adlington, rattled home for third in lane eight.
Had Boyle replicated her morning time, she'd have finished fourth. But there's no point in pondering ifs and maybes; Boyle isn't done with these Olympics yet.
Before the 400m, she had an inkling her 800m would be her better chance of making a dent at the Games. And now?
"Maybe. I've never done a faster 400m so that's got to somehow help me for the 800," she said.
"Maybe in the first 400m it could feel a little more relaxed than it used to because I know I'm able to go that much faster.
"But I'm not put off by this result. I'm really happy and there's things I can take out of it and build for the future."
Like not watching the hot shots across the lanes, where she admitted she erred.
She also knows she's got to find a way to back up from a strong morning swim.
"I've never really been in a situation where I've had to do such a fast heat and try and repeat it in a final. That's a learning curve for me.
"I didn't handle it as well as I wanted to but I think I can learn something from that."
Boyle has made substantial steps in the past year, as a person as much as a swimmer.
Sixth and eighth placings in the 400m and 800m world championship finals in Shanghai last year brought a change in outlook.
"I've learned to look at my competitors, who I used to be in awe of, and think 'I'm going to race them' instead of 'they're going to crush me'," Boyle told the Herald.
Her time at the University of California Berkeley has broadened her perspective on life.
She has a business degree from the Haas School of Business and credits the United States women's team's head coach, Terri McKeever, with much of the rounding out of her development.
"I learned a lot from her about personal growth and ... it's kind of hard to describe in words. But she made me a more confident person, in a way where [you learn that] you don't have to be good at only one thing."
If that sounds like she's ready to move on to the next stage in her life, Boyle stressed she wants to carry on.
"I'm excited. I feel like I've never had these results before and really owe it to myself to keep going."
