Williams, who scored twice during the 28-9 win over the Springboks at Coca Cola Park, feels that the quality of rugby produced by the tourists, together with the family atmosphere created in camp, provides the perfect repost to those who claim the Lions have no part in the modern game.
"We've proved the Lions have a massive future," said Williams, whose 25th and 33rd minute tries ensured the Lions left South Africa with the Test-match victory their efforts thoroughly deserved.
"I've never been on such a good tour and it's the toughest rugby you're ever going to play. Playing for the Lions is the pinnacle of my career and it is something that should continue for ever."
Williams and his colleagues played their part in a truly stunning three-match series against the world champions; one that had supporters on the edge of their seats throughout and could easily have gone the Lions' way.
Very few Test fixtures can match the drama and intensity of the three encounters in Durban, Pretoria and Jo'burg, and Williams has no doubt that such special occasions illustrate exactly why the concept of the Lions should be held sacred despite the demands of the professional game.
The 32-year-old Welsh winger epitomized the spirit of the Lions as he went looking for work on Saturday knowing that, although space might not open up for him to exploit, his efforts might instead give his colleagues that vital extra yard of freedom.
Williams was a constant threat to the Boks, continually looking to get his hands on the ball rather than waiting for glory out on his wing.
For the Ospreys star his tries were a bonus, but the real pleasure came from the performance of the team as a whole and, of course, from the win.
"It was a massive game for me. I know eyes were on me because there were a lot of doubters out there and I knew it was my last Lions game so I would have to perform.
"I wasn't going out there to dazzle but to work in players outside me. I got involved as much as I could, played first receiver, second receiver and nine when I had to.
"I could see when I got my hands on the ball that the Springboks were looking for me to do something and when I was offloading to other players, that gave me as much satisfaction.
"Our defence was incredible and we can hold out heads up high and go home happy. We have been a tight-knit family on and off the field from the start and we deserved this result.
"We've worked hard from day one and we felt we deserved something out of this tour."