Josh Griffiths, the club runner who beat Britain's elite men in the London Marathon to qualify for the 2017 World Championships on his marathon debut, says he will continue to coach himself.
Griffiths, 23, finished 13th overall in two hours 14 minutes 49 seconds, and was the first British man to finish.
The Swansea Harriers runner claimed an automatic qualifying place for August's World Championships in London.
"It's not something I planned but I can't wait to get started," he said.
Speaking to BBC Radio Wales, Griffiths added: "I currently coach myself and given my result, I might just keep doing what I'm doing because it seems to be working.
"I just love the challenge of it, I love pushing yourself and seeing how far you can take yourself."
Griffiths, whose longest competitive distance was a half marathon before Sunday's race, initially aimed to reach the Welsh 2018 Commonwealth Games qualifying time of 2:16:00.
"It's almost a completely different event because it's double the distance [than a half marathon] and double the amount of time on your feet," he said.
"It just takes different training requirements and if you prepare then you can feel ready for it.
"My legs are a little bit sore but I'm still riding a wave a little bit, I still can't quite believe what has happened."
'I expect nothing less'
Meanwhile, Griffiths' club-mate Matthew Rees stole the headlines as he helped exhausted runner David Wyeth cross the finishing line.
The Swansea Harriers pair took much of the media focus on the day that Mary Keitany won the women's race with the second-fastest time in history.
"It's great for the club and I know Matt, he's a great guy and I wouldn't expect anything less of him," Griffiths said.
"Everyone pushes to the limit, it's just those limits vary for different people.
"It's a very selfless act and you'd never know unless you were there. Hats off to him, it was a great thing to do."