Hamblin's partner Cameron Holt was watching on in Cambridge with mixed emotions.
"It was terrible to watch on TV, especially at the Olympics but that's what happens in racing."
Holt said he wasn't surprised at Hamblin's extraordinary act of sportsmanship.
"She's a really honest, kind, caring person, she's always thinking about other people and helping as much as she can, so it's just something that comes naturally to her."
Her athletics club and book store colleagues say she is "very genuine" and "always gracious".
Originally from Weymouth in Dorset, England, Hamblin moved to New Zealand in 2006.
She lives in Cambridge and trains with the Cambridge Athletics and Harrier Club.
Club president George Chambers said Hamblin was a "very genuine person".
"She's extremely humble," he said. "She doesn't boast and doesn't say much about what she's doing.
"She's always pleased to mix with others and that's what came through.
"She's had tumbles before and been injured so I imagine when she saw the American runner was still down, she would have thought 'I know what that's like'."
Chambers said the club backed her all the way and would be looking forward to her return, regardless of whether she won a medal.
"We're delighted to have her in the club. She wants to be a mentor to some of our younger athletes, which is great.
"All the younger ones look up to her."
Hamblin has worked part-time at Wrights Bookshop in Cambridge between training and competitions for several years.
Rick Wright, whose son owns the store, said Hamblin was a "neat person" who was loved by everyone.
"I'm not really surprised [about the sportsmanship]. She cheers everyone up and organises everyone when she's here.
"She goes all around the world but whenever she's in Cambridge she pops in to say hello."
Another Wrights colleague said Hamblin was "always gracious" and helpful.
"I'm not at all surprised she helped the American girl.
"She's a lovely girl and fantastic to work with. She's just one of the people of Cambridge.
"It's great that her sportsmanship culminated in her getting a second chance."
Speaking on Mike Hosking Breakfast this morning, Hamblin said she would remember the moment for the rest of her life.
"It wasn't what I expected to happen when I got out of bed this morning. From my experience when I look back at the races I've done in previous years, you don't remember the performance moments, you remember the moments like that.
"When I look back on Rio 2016, I'm not going to remember where I finished, I'm not going to remember my time but I'll always remember that moment."
Asked if she felt like a hero, Hamblin said "no, not at all" and praised D'Agostino for helping her up.
