The distance runner has become a father for the first time with the birth of son Hudson three weeks ago, he has changed his training style, and has finished taking two seconds off his personal best in the half-marathon at the Melbourne Marathon.
Threlfall completed the race in 1.06:16, taking two seconds off his previous best place, while finishing third overall.
“It was a bit of a surprise podium,” he said.
“It's a tough course to run on, quite a bit harder than at the Gold Coast where I set my PB initially, so I'm pretty happy with my result.
“Taking two seconds off a race time is a big achievement for any runner, so it's something I'm very proud of.”
It comes after a complete shakeup to his training program in the days since his son's birth.
“I've been pretty obsessive with training and how I prepare, but I already feel like I'm relaxing a bit more,” he said.
“We looked at how I train and cut down from 170km a week to around 130km. I also try and get the training done in the morning. In the past I'd do some afternoon runs, but now I'd much rather be at home.
“I don't know how this works long term, I'm figuring that out, but I want to give it the best I can in the meantime. I felt really good approaching the line, I felt like I could perform really well, so I just need to manage that going forward.”
In the event's 10km race, Archie Reid was able to claim sixth spot.
The young runner finished the race in 30:47.