O'Sullivan has his sights set on Selby and world title
Mark Selby may be the world champion, but Ronnie O'Sullivan is still regarded as the man to beat at the World Championship.
Selby begins the defence of his crown today when he takes on Norway's Kurt Maflin, while O'Sullivan starts his bid for a sixth title when he faces Craig Steadman on Tuesday.
No first time winner - Selby triumphed last year at his 15th attempt - has ever retained the World Championship.
"It is a curse and it is going to be difficult but I will just try my best. It shows how difficult the tournament is to win," said the Leicester cueman, who beat O'Sullivan 18-14 in last year's final.
"It will be a fantastic feeling to walk out at the Crucible and be announced as the defending champion. It is all I have ever dreamed of.
"I will feel a bit nervous. Even if I wasn't defending champion I'd be nervous. Everyone gets nervous.
"It would be wrong if you didn't get butterflies because it is such a great tournament and such a great venue.
"But hopefully the nerves will inspire me and I'll play better."
If O'Sullivan can win a sixth title it will equal Steve Davis's tally and be just one short of Stephen Hendry's all time record.
And Davis, who failed to make it through qualifying, feels O'Sullivan (39) still has what it takes to win the £1.25million event.
"Never discount O'Sullivan," said Davis, now 57.
"However, there is still expectation on him. That has its own pressure and if you are one of the favourites, all eyes are always on you.
"That takes its toll and you have to be very strong to withstand that for two weeks.
"I know what it did to me, I always felt the pressure."
"It is very hard to pick an outright winner with so many good players competing but you have to look at those in form.
"Shaun Murphy performed well to win the Masters, John Higgins is looking good so could be a dark horse and it will be fascinating to see if Mark Selby can break the curse.
"The second week will define who is in form.
"The British contingent will play a big part in this year's tournament and while the game is expanding worldwide, I feel a Brit will have his name on the title."
Ulster's title hope Mark Allen starts out on Tuesday against Ryan Day, the winner facing either Barry Hawkins or Matthew Selt for a place in the quarter-finals.