With one trademark step and an amazing turn of pace the winger left the Welsh fans with one final memory of his class and brilliance.
With the score at 24-11 to the Wallabies it looked like the Ospreys star was going to leave the international stage with a whimper. But the 34-year-old showed he has not lost any of his trickery as he jinxed past Berwick Barnes and Anthony Fainga to score his 60th Test try.
The elation covered the fact that Wales suffered their third-successive defeat. The 61,923 fans inside the stadium blew the roof off as everyone joined in celebrating with Williams; so much so that few even noticed Dan Biggar scored the conversion.
It was a fine way to sign off after 87 caps and 11 years at the top of his game.
The Ospreys star admitted he could not have asked for a better ending. He said: "I guess I couldn't have scripted it any better with the try. I thought the moment had gone but thankfully I was on the end of a good pass.
"It's always a better feeling when you win but that was the best atmosphere I've ever experienced, even if I'm biased.
"The crowd just added to the emotion and I couldn't contain myself in the end and started balling my eyes out.
"But my Wales career began at the Millennium Stadium and now it has ended there so I can't think of a better way to finish than with those supporters."
The 60th try of his Test career - he has 58 for Wales and two for the British and Irish Lions - leaves Williams third in the all-time try scoring rankings. Only Australia's David Campese (64 from 101 Tests) and Japan's Daisuke Ohata (69 in 58 Tests) are ahead of him and that is not bad company to be in.
Described as a 'one in a generation player' by Australia's coach Robbie Deans, Williams will be sorely missed by Wales. In Saturday's match he did more than just score that try, the diminutive winger also put in two try-saving tackles. He is dogged, intelligent and unassuming.
Williams has never taken anything for granted and he admitted before the match it is still a dream to play for Wales.
That dream is now over for Williams and Wales will have to look to the future and prepare for the 2015 World Cup without him. The number 11 shirt will be given to someone new.
It's a small jersey, but Williams's size six boots are too big to fill - for the meantime, at least.