The Yixing sharpshooter has always been one of the few players with the natural skill to match O'Sullivan's machine-gun break-building and precision long potting, but he has sometimes lacked the coolness under pressure needed to prevail in the pressure-cooker environment of the Crucible Theatre.
But at 30 years of age, Ding appears finally to have added that mental toughness to his game, perhaps helped by his work with renowned coach Terry Griffiths.
This newfound inner steel was on full show on Saturday as he completed a breath-taking 132 clearance and then a 70 break to turn the tables in his match against Liang, earning a standing ovation from the Sheffield crowd.
Ding also showed great character to bounce back from the crushing disappointment of his loss to Mark Selby in the final of last years' World Championships, winning the Shanghai Masters against the same opponent.
Liang also believes that his conqueror is now ready to go all the way.
"He has a chance to win the World Championship. Last year he made it to the final. This year he has more experience and is more confident. There are lots of good players here," said the world number 13.
Much could also depend on the mental state of Ding's opponent. Always a volatile character, O'Sullivan has spent most of the season mired in controversy, even accusing the snooker authorities of "bullying and intimidation" in the run-up to the World Championships.
Though he has performed well on the table so far in Sheffield, off it he has continually insisted that he is not taking the tournament too seriously.
"My main aim now is to travel, play exhibitions, do my punditry work and work with people outside the industry—it is fun. I can be like a band who do a world tour - they pitch up, they play and it is all very nice for them because there is no pressure. I enjoy being in that position more," said O'Sullivan after his second round win.
If Ding is able to put the veteran under pressure, there is a chance he will not be prepared for the gruelling mental battle of an eight-hour match.
Whichever player emerges triumphant, there are sure to be fireworks as two of the most exciting players in the sport cue off on Tuesday, watched by an expected audience of 150 million people.
There is also sure to be huge anticipation in Ding's hometown of Wuxi, where the Snooker World Cup will be held in July and where Ding won the Wuxi Classic in 2008.
But the man carrying China's hopes is trying to keep a level head.
"A lot of people will be interested in me playing Ronnie, but I don't feel that when we are playing. The frames are more important than who is watching and I need concentration," said Ding.
