The 46-year-old is in action today as he takes on Englishman Sam Craigie in the first round of this year’s World Snooker Championship. Williams, who has won the world crown three times, is aiming to surpass his efforts in last year’s tournament, where he lost to eventual winner O’Sullivan in the quarter-final. Nicknamed The Welsh Potting Machine, Williams is regarded as one of his generation’s best snooker players, and has endured a three-decade rivalry with O’Sullivan – and Scot John Higgins.
Across the years, Williams has faced O’Sullivan 48 times, but boasts a miserly 25 percent win ratio, compared with his rivals 68.75 percent.
And when Williams was preparing to face O’Sullivan in the 2014 International Championship quarter-final, he confessed the man nicknamed The Rocket was his “bogeyman”.
Williams hadn’t beaten O’Sullivan in more than a decade ahead of that match, but thankfully for the Welshman he would put that run to bed with a six frames to five win.
Although unaware he would prevail, Williams also tore apart his poor performances against O’Sullivan.
The 2018 World Snooker Championship winner said: “Ronnie has been a pain in my a**e for 12 years.
“People say he’s my bogeyman, but to be fair he’s a lot of people’s bogeyman – and if you have to have one I’m happy it’s him.”
According to Inside Snooker, Williams said that although he had got the better of him in some games, such as the 2002 Thailand Masters, O’Sullivan was “always hard to beat – but even harder for me now”.
He added: “He doesn’t play many events but he’s still by miles the best player in the world.
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“John Parrott is the one that stands out for me in my career, he beat me the first I can’t remember how many times.
“He just seemed to play really well against me. Everyone has a player that brings the best out of them.”
O’Sullivan is already into the second round of this year’s championship, which is taking place at Sheffield’s The Crucible Theatre.
The longevity of O’Sullivan, Williams and Higgins’ career is remarkable, considering they all turned professional in 1992, with the trio still aiming to add to their collective 13 world crowns.
O’Sullivan has been scathing in his assessment of the state of snooker as a result, and questioned last year why the three men in their forties were still able to challenge for trophies.
He told the BBC: “If you look at the younger players coming through, they’re not that good really.
“Most of them would do well as half-decent amateurs, or not even amateurs they’re so bad a lot of them.
“A lot of them you see now, you think, cor, I’ve probably got to lose an arm and a leg to fall outside the top 50. So that’s why we’re hovering around – because of how poor it is down that end.”
But prior to this year’s Masters in January, O’Sullivan claimed Williams “definitely can” still compete and have a say in who wins the sport’s biggest titles.
He added: “I think definitely him and John Higgins can still win titles, but it is going to be really hard.
“The top three are there and are probably going to win 60 or 70 percent of the tournaments they play in, that we all play in, so it only leaves those other opportunities. And you’ve got Mark Allen, Ding Junhui, Barry Hawkins, Stuart Bingham, a lot of players, and they’re going to win tournaments as well.
“If you’re an exceptional player you can probably do what [John] Higgins and [Mark] Williams have done, which is compete, but it’s still downhill for them.
“They’re still not the players they were, yet they were so good that even their B or C game is allowing them to compete and allowing them to have the odd good tournament.”