O'Sullivan 'struggled to stay awake' in Crucible upset
Ronnie O'Sullivan revealed he felt "horrendous" and struggled to stay awake as he crashed out of the World Championship to amateur James Cahill.
World number one and five-time champion O'Sullivan went down 10-8 on Tuesday in one of the Crucible's great upsets.
The defeat was particularly surprising given O'Sullivan's sterling season, with wins at the UK Championship, Players Championship and Tour Championship taking him back to the top of the rankings.
Yet the 43-year-old said that he felt lethargic over two days against Cahill, explaining a sloppy performance.
"I'm alright, all my limbs just feel really heavy - legs, arms," O'Sullivan told BBC Sport. "I'm absolutely shattered, just drained really, had no energy.
"I was struggling, struggling to stay awake. I haven't got any visual stuff. I just feel horrendous, to be honest with you.
"You have to come here physically, mentally feeling good. Mentally I was up for it - I've had a good season.
"I didn't expect to do well here, you just try to do your best. If you're physically not 100 per cent, then it's going to make it even harder.
"I tried to hang in there, tried to do as much as I could and see if I could get through this match and then have a few days off to feel a little bit better."
Cahill almost let O'Sullivan back into the contest at 8-8 and admitted that he found it difficult to adapt to facing a modern great who was so out of shape.
"It was hard to play against, because you don't expect him to miss so many balls," he said. "I was quite happy with it at 2-2, 3-3, when I was potting and he was potting and it seemed normal.
"Then when he starts missing a few, you come to the table and think, 'I've got a chance now'. Then it happens again and you miss a couple and it sort of catches on.
"I've gone out there today and tried to be professional and not take on too many things. I've tried play my own game really - it's easy to get dragged into other people's games."