Douglas knocked 0.23 seconds off her previous best time
Montell Douglas broke the British women's 100m record at a meeting in Loughborough on Thursday to seal her place at the Olympics.
The 22-year-old Londoner, assisted by a following wind of two metres per second, clocked 11.05 seconds to beat Kathy Cook's long-standing mark.
Douglas was already in the 4x100m relay squad for Beijing, but will now be included in the individual sprint.
"It's given me a massive amount of confidence," she said.
"It was now or never - I had to prove myself. It feels surreal and I can't even comprehend it."
With the benefit of the maximum legally permitted tailwind, Douglas smashed her previous personal best of 11.28.
Douglas, the European Under-23 silver medallist, finished second behind Jeanette Kwakye at the Olympic trials last week.
Her official confirmation as one of Team GB's entrants in the individual 100m should come on Saturday.
Cook, the 1984 Olympic 400m bronze medallist, posted her record of 11.10 in Rome almost 27 years ago.
Douglas, who had run a 10.95sec wind-assisted time in her heat, added: "The key thing for me was self-belief.
"I didn't run to the best of my ability at the trials so I pit a bit of pressure on myself.
"My coach Ayo (Falola) has been brilliant this year. We have worked so hard and it was time to step it up and produce and we have done that."
My mum said to me this week 'fly like a bird' and my physio said to me 'run like the wind'
Douglas, studying sports science at Brunel University, added: "After the heat, he said I just have to do the same again for the final and I did.
"My mum said to me this week 'fly like a bird' and my physio said to me 'run like the wind'.
"Those two sayings have been going round my head all day and I managed to do them."
Douglas will be racing in the 100m at the Aviva London Grand Prix at Crystal Palace on 26 July against US and Jamaican stars Allyson Felix and world champion Veronica Campbell.
She will also be involved in another head-to-head with British number one Kwakye.