Cumbrian runner Oliver Dustin pledged that his Olympic experience had made him "hungrier" after missing out on an 800m semi-final place.
The 20-year-old finished sixth in his heat in Tokyo, a time of 1:46.94 not enough to see him to the next stage.
But the Workington athlete said he would learn from the experience and return stronger.
“I just didn’t have it today, I don’t know why it wasn’t there,” said Dustin after the race.
“I don’t think I’ve had anything wrong coming in here – training camp went well, odd little niggle but nothing major. Off the top of my head, nothing.
“I’ve done everything I can, and it wasn’t there today. And that’s the way this sport goes.
“You can be on top of the world one day and it’ll kick you in the teeth the next. I have learned from it, and I’ll be back, I’ll definitely be back stronger. It’s only going to make me hungrier.”
Dustin had been im impressive form in qualifying for the Olympics, finishing second at the British Olympic Trials in June, having also gone sixth on the British all-time list and broke the national Under-23 record in Nice in June.
Dustin's preparations for Tokyo then saw the Border Harrier at the centre of reports that traces of cocaine had been found in a drug test - before he was cleared of any sanctions after the sample was found to have been cross-contaminated.
The runner has spoken about the difficulty of dealing with that situation at such a crucial time in the build-up to his first Olympics.
He said: “It was hard to process something that was so wrong, and I can’t say too much but it was a massive injustice against me and as an athlete that’s the last thing you expect to happen.
“It’s difficult, it was difficult to be at such an emotional low point and then think, 'I’m going to the Olympic Games now'.
“But I am much stronger for it and its taught me a lot about the sport and I’m going to be here for a long time, so I’ll speak to you a lot over the next couple of years, but it’s made me much stronger as a person and as an athlete.”
Team GB's Elliot Giles and Daniel Rowden made it through the 800m heats.
No one does more to support our Olympic and Paralympic athletes than National Lottery players, who raise around £36 million each week for good causes including elite and grassroots sport. Discover more about how playing The National Lottery supports Team GB’s athletes by visiting www.national-lottery.co.uk/tokyo2020 and get involved by using the hashtags: #TNLAthletes #MakeAmazingHappen
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here