American Luke Guthrie took the lead at the midway point of the Honda Classic, but it was Rory McIlroy who stole the headlines. Guthrie shot a brilliant seven-under 63 at the PGA National Champion Course in Palm Beach Gardens to lead by a stroke from compatriot Michael Thompson. But world number one McIlroy had a day to forget, walking off the course when he found water on the 18th – the Northern Irishman&aposs ninth hole of the day. To that point, the defending champion was seven-over par for the day, and later accredited his withdrawal from the PGA Tour event to a sore tooth. McIlroy&aposs disastrous day is merely a subplot to his decline in form in 2013, which has been under tight scrutiny due to his multi-million dollar switch from Titleist clubs to Nike. Thompson is outright second after carding a five-under 65 on Friday, from American Boo Weekley and Graham DeLaet of Canada – who are level on seven under, two behind leader Guthrie. Further back, England&aposs Lee Westwood produced another consistent round to be tied for fifth on six under, level with countryman Justin Rose, Australia&aposs Geoff Ogilvy and Americans Doug LaBelle II, Charles Howell III and Sean O&aposHair. McIlroy wasn&apost the only big name to struggle in Florida, although at least Tiger Woods can say he is still in the tournament, albeit only just. Woods scraped past the cut when he recorded consecutive even-par 70 rounds, but needed a birdie on 14 to make back shots lost on 13 which he double-bogeyed. Colombian Camilo Villegas went from hero to villain in the space of 18 holes, as his first-round lead wasn&apost enough to get him through to the weekend as he missed the cut by a shot due to a round of seven-over 77.