Across countless half marathons, getting closer and closer to a winning time, Threlfall kept pushing to reach his goal.
On January 12, it finally happened.
And the Moama runner could not be happier after claiming the Cadbury Half Marathon in Hobart.
“It's honestly the biggest win of my career,” he said.
“I've been building towards this for so long, and while I've occasionally put down a really good time or made it on to a podium, getting the win is something very special.”
Threlfall spent seemingly the whole race going head-to-head with fellow runner David Ridley, as both gave their best to edge each other out.
The battle would come down to the final stages of the race before Threlfall was able to break away and get the win.
“David is on the New Zealand team for the world half marathon championships, so he was never going to be an easy runner to go against,” he said.
“We cleared out from the rest of the pack after about a kilometre or so, and we started having a good old fashioned race. He's stronger than me, but I probably have the top end speed.
“It was a challenge as he tried to get me a few times but I was able to keep with him through those stages, so in those final few hundred I broke past him and was able to hold on and get past him.
“We got down to about 300m left and we were still neck and neck. I set the plan to try and out sprint him in the final stages, which is exactly how it played out.”
In the end Threlfall put on the afterburners, claiming the race in a time of 1.07:09, ten seconds in front of Ridley.
“I've been down there a few times and have finished fourth before, so it was huge for me to finally get a win in one of these bigger races.
“You often run PBs or get on the podium in these bigger events, but finally claiming one is really special to me.”
It's yet another accolade to add to his career since the birth of son Hudson last year.
Since then he has finally completed a life long goal in running a sub-30 minute 10,000m.
And Threlfall doesn't believe it is a coincidence.
“I don't have as much time to train anymore,” he said.
“I'm not setting life around my training, it's more when training when I have the opportunity, and I'm not stressing as much as I was. My focus has shifted, and it's had a really positive impact.
“Running doesn't matter as much, as long as the family is ok. But you also have the extra motivation of doing it for the family at home.”
Now the goal is to translate the form into the longest form there is.
“I have the Rotterdam Marathon in April,” he said.
“It's a good flat course, has had a world record set on it before, and will have a lot of competitors at my pace.
“I'm feeling pretty good with the recent runs in the half and the 10k, hopefully I can convert that over to the marathon.”