Ronnie O'Sullivan into World Snooker Championship quarters

Defending champion Ronnie O'Sullivan cruised past Ali Carter 13-8 to reach the quarter-finals of the World Championship in Sheffield.

O'Sullivan looked composed in the first session, taking a 5-3 lead, but Carter held himself together in the next to stay in touch at 7-9.

But it was all O'Sullivan in the final session, rattling in a century as he dropped only one of five frames played.

The result sets up an all-Essex last-eight clash against Stuart Bingham.

O'Sullivan, seeking to win his fifth Crucible title, only returned to snooker at the start of the tournament after a self-imposed 11-month sabbatical from the sport.

And while world number one Mark Selby - who lost to Barry Hawkins - said he felt "burned out" as a result of playing too much snooker, the break appears to have done 37-year-old O'Sullivan, who seemed fresh and invigorated, the power of good.

O'Sullivan said: "I am pleased to get through. Even last year, quite a few times I felt it was slipping away but you have to stick in there and take each pot at a time.

"You have to realise it is not a sprint but a marathon. I knew this would be a proper test against Ali. It is not going to get any easier and you just have to keep plodding along."

Two-time world runner-up Carter, who threatened to retire in 2011, remains winless in 13 attempts against O'Sullivan in a ranking-event match - something which BBC pundit and seven-time world champion Stephen Hendry described as "tough" to get over.

"Ronnie plays like this every time I have played against him - no wonder I haven't beaten him," said Carter, who has suffered for much of the last two years from the debilitating bowel condition Crohn's disease.

"I was there trying to win, not avoid defeat. It was a tough day today and he did not do anything wrong. Ronnie will go on to win it if his head doesn't fall off."

In a repeat of last year's final, breaks of 78, 66 and a sublime 125 allowed 'The Rocket' to surge ahead in the first session.

After 'The Captain' won four of the next five frames to make it 7-7, O'Sullivan took the last two, courtesy of breaks of 73 and 86, to sneak ahead going into Monday evening's decisive session.

Both players had their chances in a tense opening frame, but it was O'Sullivan who went further ahead.

Carter pulled a frame back, but his opponent took the next two with breaks of 88 and 106 to move within a frame of victory.

And there was to be no miraculous recovery as a knock of 89 proved enough for O'Sullivan to progress.

You can follow all of the quarter-final action on BBC Two, the BBC HD Channel and online from 10:00 BST on Tuesday