The 22-year-old, from Edinburgh, currently based at the University of Tulsa in Oklahoma, thought he had done enough to earn selection for either the European Championships or Olympic Games last year but gained an invite to neither.
His exclusion, he concedes, has left him with multiple points to prove but he all but sealed his place at next month's World Championships in Moscow with victory in the 1500 metres final at the British Championships in Birmingham yesterday.
O'Hare surged away on the final bend to claim victory in a race that also featured fellow Scots Kris Gauson, David Bishop and Ali Hay. With the secondary B qualifying standard for the World Championships already achieved, the title pushed him to the brink of selection but not quite over the line.
"I assume I've done it but I wouldn't want to go celebrating like I'm in the team," O'Hare said. "There will be time on Tuesday [when the British squad is named] for that. Hopefully I'll be a happy boy."
The personal best of 3:35.27 that O'Hare established in Belgium eight days ago suggests he is breaking new ground. He added: "I do think that if I'm given the opportunity to run at the Worlds I'll be able to pull faster times out of the bag and hopefully get through more than one round."
Despite soaring temperatures in the Midlands, many athletes succeeded in keeping their cool. The performance of the day came from sprinting prospect James Dasalou, who now trails only Linford Christie on the British 100m list after surpassing his previous best with an astonishing run of 9.91secs in the semi-finals.
A bout of cramp forced him to withdraw from the final, leaving 35-year-old Dwain Chambers to claim a fifth UK title. Yet Dasalou, who has fought a mélange of injuries, now looks set to challenge the current Jamaican-American duopoly at the distance. The 25-year-old said: "I made the semis in London and I would love to go one better in Moscow and get to the final. Of course, once you make the final anything can happen."
Like a pair of prize fighters at a weigh-in, Eilidh Child and Perri Shakes-Drayton did a little shadow boxing in the heats of the 400m hurdles. They square off for real this afternoon with the Scot, fresh from lowering her own best on the same track two weeks ago, bidding to erase a run of 13 consecutive knockouts at the hands of her long-time rival. Both won their heats, with Child achieving the quicker time despite the introduction of a tweak to her stride pattern. It is likely she will revert to her tried-and-tested approach for a showdown which might push both Britons past their previous limits.
"It's really good to go up against Perri because we always seem to bring the best out of each other," Child said. "Perri's one of the best athletes in the world this year and I'm lucky in that I get to race against her a lot. So when it comes to the World Championships and races like that, I'm not scared because I race her all the time."
O'Hare apart, two other Scots claimed UK titles yesterday although neither exhibited the pedigree to push their way into the world squad. Andy Frost, rebounding from missing 2012 through injury, was a surprise victor in the hammer, out-shining both reigning champion Alex Smith and also Mark Dry, who squandered a glorious opportunity to stake a claim by coming a lowly sixth.
Emma Nuttall delivered a lifetime best of 1.87m to claim her first high jump title before failing at 1.90m. "It's so close," she said. "But with another winter of hard work, and an indoor season, I'll be going 1.90-plus at the Commonwealths, hopefully."
Dai Greene held off Welsh rival Rhys Williams in the 400m hurdles as he prepares to defend his world title. Olympic silver medallist Christine Ohuruogu won the 400m title, with Scottish prospect Kirsten McAslan fifth.
o Laura Muir booked her place in tonight's 1500m final at the European Under-23 Championships in Tampere, Finland, by coming second in her semi. Allan Smith (high jump) and Jax Thoirs (pole vault) will also be in contention for medals.