Competing in a Tasmanian Christmas Carnival meet on Tuesday night at Penguin (population 3,849 at last count), McSweyn powered to victory in the mile race in three minutes 50.61 seconds.

It was the fastest mile run anywhere in the world in 2020 and the quickest by an Australian in 15 years.

"Penguin's probably not a place most people associate with running fast so it was pretty cool to put up such a good performance in front of a great crowd," said McSweyn, who hails from nearby King Island.

"It's one of those old tracks liked you'd find in many places around Australia.

"Obviously nowhere near the standard of the tracks we get in Europe, especially in the Diamond Leagues.

"But for a rural place it was a really decent track."

The win capped a remarkable season for the 25-year-old, who also broke the long-standing national 1500m and 3000m records on the Diamond League circuit and is now shaping as a genuine medal shot at the rescheduled 2021 Tokyo Olympics.

While many of Australia's biggest track and field stars chose to remain home due to concerns around the COVID-19 pandemic, McSweyn and his Melbourne Track Club teammates headed to Europe for the northern hemisphere summer.

It proved an inspired decision, even though the likes of McSweyn and training partners including Ryan and Genevieve Gregson, Brett Robinson and Matthew Ramsden had to endure a nervous two-week wait in London before finally securing a flight home in late October.

Then there was a compulsory two-week stint in quarantine in Brisbane, which at least allowed McSweyn to catch up on his university studies.

"Definitely we've got an advantage," McSweyn told AAP.

"I was able to use 2020 as a practice run for 2021.

"I was running my best at the time when the Olympics would have been and when they will be hopefully in 2021.

"Having a lot of high-standard races overseas gave us an advantage because it's hard if you've had a year off to try and find your best again straight away."

McSweyn's favourite performance of the year came in Doha in late September, when he claimed a dominant victory in the 1500m to consign Ryan Gregson's 10-year-old national mark to the history books.

"Not because I broke the record but purely because I was able to execute the race I wanted to execute," he said.

"The Diamond League is where everyone is watching and you can put yourself on the map.

"That's the biggest race I've ever won."

McSweyn has yet to decide on his racing program for the Tokyo Games, although the 1500m is shaping as the No.1 priority.

Australian Associated Press