"I tried to get close to kick him but I don't think I could even kick him," Cahill said in Sydney on Wednesday when asked to reflect on Australia's 2-0 defeat against Brazil in 2006.
At the time he faced the Socceroos, Ronaldinho was the reigning Ballon D'Or winner, and his gifted feet made him the embodiment of the Brazilian mantra of "joga bonito" (play beautifully).
He is in Sydney this week as part of a venture with Cahill aptly called the Joga Bonito tour, where a Cahill XI will face a side put together by the Brazilian legend.
Sides chosen by Tim Cahill (left) and Ronaldinho will do battle on the Joga Bonito Tour. (Dan Himbrechts/AAP PHOTOS)
Since their encounter at the World Cup in Germany, Ronaldinho has fallen on harder times.
The former Barcelona star was once the best-paid player in the world but has been facing huge tax bills and was jailed for attempting to enter Paraguay on a fake passport.
Ronaldinho got one over on Cahill nearly two decades ago, but the Brazilian side oozing generational talent was eventually knocked out in the quarter-finals by France.
Brazil haven't won a World Cup since, and they were criticised in 2006 for enjoying themselves away from the field and for abandoning the nation's footballing ideals.
"We were not the real Brazilian national team, the one with creativity and classy touches," midfielder Kaka said at the time.
Ronaldinho was the poster boy of that Brazilian team and still received the acclaim of a demi-god when he came face-to-face with Cahill overlooking the Harbour Bridge.
The 44-year-old arrived with a legion of heavies and hangers-on, and to a large media crew.
Cahill's XI will be coached by Graham Arnold in his first venture since exiting the Socceroos job, and also contains Aaron Mooy and Football Australia board member Heather Garriock.
According to the website of CommBank Stadium, which will host Friday's game, Ronaldinho's XI includes Shane Smeltz, Henrique Silva, "along with the skilled goalkeeping of Cassio Oliveira", who was famously a defender.
It also contains an Australian social media influencer, giving a sense that this event - where the cheapest child's tickets start from $60 - is arguably more about driving exposure and revenue than anything else.
The event is partially sponsored by electric vehicle manufacturer BYD, for whom Cahill works as an ambassador.
"The most important thing about creating this game was about activating grassroots and inspiring the next generation of footballers in Australia to follow their dreams," Cahill said.
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