The 22-year-old played the whole game at full-back with a licence to attack and created several chances with his pace down the right wing.

Goals from Atkinson's past and present Melbourne City teammates Lachy Wales, after 14 minutes, and Marco Tilio, 10 minutes from the end, proved the difference at the Sapporo Dome.

Commentator Andy Harper heaped praise on the Launceston-born Riverside Olympic product who had also been judged best player in last month's A-League Grand Final victory over Sydney FC.

"Nathaniel Atkinson had a brilliant end of the season," Harper said. "We all thought his Olympics were dead and buried a year ago through suspension and then this year through a terrible hamstring injury and then he finished the A-League so strongly with the Joe Marston Medal on grand final day and now finds himself representing his country.

"He's been outstanding ... superb, probably Australia's best on balance ... an eye-watering performance down the right-hand side."

Argentina had defeated Australia en route to Olympic gold medals in 2004 and '08 but were second best on a night when the Olyroos topped Group C following the earlier goalless draw between Spain and Egypt.

Atkinson is the second Tasmanian soccer player to compete at an Olympic Games after Hobart-born former Marconi defender Dominic Longo was in the 1992 team in Barcelona.

Having made a miraculous recovery from a grade-three hamstring tear to play in the A-League decider and Olympics, Atkinson was one of seven Australians to collect yellow cards against Argentina, which could lead to a suspension if any get a second in the remaining group matches.

Graham Arnold's side will face European heavyweight Spain at the same venue on Sunday at 8pm, before its final group-stage match against Egypt at the Miyagi Stadium on Wednesday at 8.30pm.

Even before arriving at the Olympic Games, Tasmanian Daniel Watkins had a good idea what awaited him at the Tokyo paddling course.

The 25-year-old Derwent Canoe Club member took part in a training camp at the Kasai Canoe Slalom Centre in October 2019 and warmed up for his return competing at comparable courses across Europe.

"It's a pretty good course," Watkins said. "It had just been finished and turned on when we were there so they were still configuring the bollards. It's probably the smallest Olympic venue so I expect quite tight racing and I think there won't be much margin between us all.

"Often Olympic venues are bigger than the world cups and that spreads the field out a bit. This has less gradient but the difficulty of the whitewater means it is probably an easier course to navigate.

"There's a lot more control with the plastic obstacles but the whitewater can take its own path and there is always an element of change. It's definitely not the biggest, but it's pretty good quality."

Watkins will compete in the C1 with heats on Sunday and the semi-final and final the following day.

Also selected as a reserve for K1, he has been preparing for a maiden Olympic Games by contesting world cups in Prague and Leipzig before a week at the Paris venue which will stage the next Olympic competition in 2024.

"Paris should be the most similar course to Tokyo that there is," he said.

"Most courses in Europe date back to about the '90s and feel quite different, but everything built in the last few years has mostly been by the same company including London, Rio, Tokyo and Paris, although Rio and London have a bit more gradient."

Hobart-born Watkins splits his time between his home in Grove, training on the Sydney Olympic course at Penrith and competing around both the globe and his home state.

"My favourite course is near Ljubljana in Slovenia which has a really big drop at the top - a bit like Bradys Lake which is another favourite of mine."

A multiple world championship representative, Watkins is proud to continue a Tasmanian Olympic paddling record by following in the wake of Peter Genders, John Doak (both 1984), Daniel Collins (1992, '96 and 2000), Peter Eckhardt (1992) and Justin Boocock (1996), with Collins winning a bronze medal in Atlanta.

Launceston duo Richie Porte and Jake Birtwhistle both jumped on their bikes to get the lie of the land in Tokyo.

Birtwhistle posted a series of pictures on Instagram detailing his arrival in Japan including a training ride with Australian teammates, along with the message: "Bit of everything on the cards today, adjusting to life in the athlete village and taking it easy after travel."

The 26-year-old triathlete will contest the individual triathlon at Odaiba Marine Park on Monday at 7.30am and be part of Australia's mixed team relay on Saturday, July 31, from 8.30am.

Meanwhile Porte was pictured training with INEOS Grenadiers teammate Rohan Dennis in front of Mount Fuji which the pair will tackle, along with fellow Aussies Luke Durbridge and Lucas Hamilton, as part of Saturday's daunting 244-kilometre road race.