Barry McClements was the only Irish athlete in action during the heats on day five of the World Para Swimming Championships at the London Aquatic Centre and just missed out on a final place.
McClements produced a strong performance to finish in fourth place in his heat but missed out on a spot in the final by .05 second, the second time this week that he has missed a final by less than half of a second.
The 17-year-old Ards swimmer, who was the youngest swimmer in the pool, adopted a bold strategy by leading from the front in the early lengths.
McClements was second after 100 metres and even took the lead after the third length before falling back to second at the fourth turn and from there on he maintained fourth place. In an agonising final length he couldn't quite find the extra burst he needed to secure a qualification time for the final.
After missing five weeks out of the pool with illness at the beginning of the summer, McClements was happy with his performance, despite narrowly missing out on a place in the final.
"Obviously I missed the 100m fly by 0.2 of getting into a final, clearly I was mentally strong enough to try and get into another final there, so ya, I’m happy with myself," he said.
"That’s my first time swimming the 400m against the world record holder, Brendan Hall.
"That guy is basically a legend in this class. It's a good experience swimming against some of the best athletes in the class as well."
McClements will return to the pool on Saturday for the 200m individual medley. Amy Marren was also due to compete this morning but injury has prevented her from competing.
Things did not go to plan for the Ireland relay team of Ellen Keane, Amy Marren, Nicole Turner and Ailbhe Kelly on Friday night as they suffered a disqualification in a race where Great Britain set a new world record of 4:36.31.
The race marked the last international race for Kelly, who announced her retirement earlier this week.