Williams will go down in history as one of Wales' best-loved players but it is Cardiff Blues clubmate Warburton who now appears to be the future of the Welsh back row.
The 22-year-old will skipper Wales when they face the Barbarians on June 4 in a match in which he will line up against his mentor for both club and country.
And although the pair are battling for a World Cup spot, Williams has made it clear that he believes Warburton will be wearing the No7 shirt for Wales and the Lions for years to come.
"He's a great athlete, he's physical, very strong, defensively he's an animal and he carries very well," was Williams' assessment of the man who has taken over from him in the Welsh openside berth.
"It's the top two inches with Sam. He's the first to analyse his game and always wants to improve. He's going to get better and better.
"He's probably taught me more than the other way around. He keeps his feet on the ground and will become a huge star for Wales and a British & Irish Lion several times."
While Williams' praise for Warburton is obviously more than just lip service, it's clear that the feelings are reciprocated by his former understudy.
Warburton has always had the utmost respect for Williams and has learnt a great deal from country's 98-cap flanker during his limited time as a professional.
"Playing against Martyn will be interesting and certainly different to training against him," added Warburton.
"He's someone I've looked up to ever since being a teenager playing rugby and it still seems strange being in the same squad let alone playing against him.
"He's been a massive part of my development and I probably have more respect for Martyn than any other player.
"He's been really supportive and may not know it but I study parts of his game very closely. I try to take the good aspects from his game and implement them into my own. That's easier said than done because he's such a quality player."