Lisa Dobriskey is a former Commonwealth champion and world silver medallist, but simply being on the start line at the Olympic stadium for today's first round of the 1500 metres will be her greatest achievement yet.
The 28-year-old, from Ashford, has overcome a life-threatening illness to compete in London after being diagnosed with blood clots on her lungs earlier this year.
Her recovery has been nothing short of remarkable after she was initially told by a specialist to give up on the Games.
"Touch wood I've been really healthy, I've made massive progress in a really short space of time," the Ashford athlete said.
"Even in myself I feel much better. There is no danger in me running. "Thankfully I am out of the woods now.
"This year has been my biggest achievement, overcoming such serious obstacles.
"I took a lot of things for granted, particularly at the height of fitness, but this time around I am so grateful for every round."
The clots led to a vastly-reduced lung capacity, a problem which was picked up by hospital scans after Dobriskey had reported problems breathing at the end of training sessions.
She was put on medication to thin the blood and the latest scan, before last month's trials, revealed a dramatic improvement in her condition.
Things have continued to look up - she has run her three fastest times of the year since then - and her timing could scarcely have been better.
"I feel I am picking up a bit of momentum at the right time," she said.
Now the task for Dobriskey is to help make up for her agonising fourth place at the Beijing Olympics.
Despite having a gold medal from the 2006 Commonwealth Games in Melbourne and a silver from at the 2009 World Championships in Berlin, missing the podium four years ago is still a source of disappointment.
A medal would be an almighty ask for an athlete who has had to cope with such extreme fitness troubles, but she is determined to make the most of her unexpected chance.
"I felt in Beijing I missed an opportunity and opportunities come round so, so rarely," she added.
"I don't want to make the same mistake again so I have to have my wits about me and make sure the chance does not pass me by.
"I feel the crowd will give me that extra little edge. Having 80,000 people screaming at you coming down the finishing straight will be amazing."
The 1500m in London will take place without this year's world leader, Moroccan Mariem Alaoui Selsouli, who tested positive for a banned diuretic.
Selsouli only returned last year from a two-year doping ban.
The news is all too depressingly familiar for Dobriskey, who has been denied a medal by a drug cheat in the past.
"It's always sad when athletes test positive," said Dobriskey, who was in tears after finishing fourth at the European Championships two years ago, beaten by a French athlete, Hind Dehiba, back from a two-year EPO ban.
"The 1500m has a shadow of drugs and cheats, but you just have to believe they will be caught.
"I think it's getting close to a level playing field."