Rory McIlroy has revealed that he was suffering from sunstroke during his second round at the DP World Tour Championship in Dubai.
The Northern Irishman still shot a 67, which followed up his opening score of 66 to tie Luke Donald and Marc Warren for the lead at the halfway stage.
McIlroy admitted that he is struggling to cope with the heat in the United Arab Emirates, but is confident of challenging for the weekend.
"I got off the course last night and had a really sore head and a fever," said McIlroy after carding a 67 in round two. "I think it was a bit of sunstroke.
"I took a few things and felt better, but I'm not feeling great again. The sun's taking it out of me a little bit but I'll be okay tomorrow.
"I'm driving the ball really, really well. I feel if I can take advantage of that then there could something in the low 60s out there for me."
South African duo Louis Oosthuizen and Branden Grace are both one shot behind the leaders on 10-under-par.
