Ronnie O’Sullivan was “struggling to stay awake” during shock defeat to James Cahill

Ronnie O'Sullivan has blamed exhaustion for his shock first-round defeat to amateur James Cahill at the World Snooker Championship

O'Sullivan didn't look his usual clinical self throughout the match, with the five-time world champion admitting that he struggled to keep his eyes open at stages of Tuesday's session at the Crucible. At the midway point of what many are calling the biggest defeat in snooker history, Cahill enjoyed a 5-4 overnight lead and O'Sullivan could not manage a dramatic comeback against the first amateur to ever qualify for the World Championship in Sheffield. "Yeah I’m alright, all my limbs just feel really heavy – my legs and arms – I feel absolutely shattered, just drained really," O’Sullivan told the BBC after the 10-8 defeat. "I had no energy, struggling to stay awake. I haven’t got any visual stuff, I just feel absolutely horrendous to be honest. "You just can’t choose. You have to come here physically and mentally feeling good, and mentally I was feeling up for it. I’ve had a good season. I didn’t expect to do well but you just come here and try to do your best and if you’re physically not 100 per cent then it’s going to make it even harder. I just tried to hang in there and do as much as I could and just see if I could get through this match and have a few days off and just try to feel a little bit better." Cahill will now face Scotland’s Stephen Maguire in the second round and while O'Sullivan, who failed to make it out of the first round for the first time since 2003, gave his 23-year-old opponent credit, it was clear that he felt more responsible for how the match played out. "Well there’s two ways you can look at it," added O’Sullivan. "You can look at it in a way that he’s come here and played brilliantly and fair play to him, or you can also look at it as I left him pretty easy chances that allowed him to gain confidence. So there’s two ways you can look at it but whatever way you do look at it you have to give credit to him that he finally got over the line."