Andrew Coscoran has qualified for the semi-finals of the men's 1500 metres in Tokyo as one of the fastest runners outside of the automatic qualifiers.
Coscoran finished eighth in his heat as he showed tremendous resolve to finish strongly, passing three runners in the final 100 metres, and advances as a time qualifier.
The first two heats were slowly run, including no fastest qualifiers from the second heat, which meant the Balbriggan man's time of 3:37.11 was enough to reach the semi-finals.
It means he is inside the top 25 in the world.
The 25-year-old only secured his Olympic qualification in June in Santry.
Coscoran's semi-final will be from noon on Thursday, Irish time.
Speaking to RTÉ Sport, Coscoran said: "I'm chuffed. I knew coming into this that I was ranked 41st in the Road to Toyko rankings so I knew it would take something big to get to the semi-finals. I just went out there and hurt.
"It's hot, uncomfortable, I knew a lot of lads would struggle with the pressure and the heat, but I went to hurt and it was good enough.
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"I saw the second heat and saw that it was slow so I knew there was a chance. I just went out and ran hard."
The Balbriggan man admitted that reaching the semi-finals was unexpected and that it took a big performance to advance.
He will be the outsider in the semi-final field after defying the expectations.
To be fair, that is one of the best races I ever had
He stated: "At the end of the day I probably wasn't supposed to make the semi-finals! We'll have to reevaluate now!
"It's a different world here. I think I was the second slowest guy in this race and technically actually the slowest so I did well to get through. To be fair, that is one of the best races I ever had."