Southampton-based Stacie Powell set a new British record as she confirmed her Olympic place at the British Gas Diving Championships in Sheffield.
Powell, who trains with Southampton Diving Club, was left in tears as she upset her higher-profile rivals to collect gold, and a London berth, in a hotly-contested women's 10 metre platform title.
Her victory that left a capacity crowd roaring though, as she snatched victory with the final dive to edge out favourites Tonia Couch and Monique Gladding with a personal best 376.05.
"I'm really, really pleased with my performance," Powell told Press Association Sport.
"Up there for that last dive, I knew being the last diver I had to do it well.
"I knew I could do it. Although it was easy to think of what it meant and the pressure that was on me I just tried to stay focused.
"I thought I'd just show everyone that I was ready to start peaking for the Games."
The 26-year-old, who studies astrophysics at Cambridge University, was mobbed by well-wishers after her victory which left her in tears.
"When everyone comes up and rushes up to you and all the months of training have been made worth it," she said.
"A home Olympics will mean everything."
Couch and Gladding will wait to find out whether they will join Powell in London with a British Diving selection panel to decide between the two on Monday.
Gladding would be the emotional choice as she almost died after hitting her head on the 10m platform at a meet in Russia last February.
The 30-year-old admitted she had since almost given up on her dream of a first Olympics before a stunning recovery, that culminated in her PB today, and has left her hanging on Monday's announcement.
"It will be a third time I've gone for it and to be in London after the year I've had would be amazing," she said.
"I've had to dig deeper than ever over the past year. Hopefully it will come together for me.
"There was a definite period where I started doubting it.
"Hopefully I'm good enough to be on the team. I've given everything I've got. I can't give any more."