Kiwi Michael Campbell showed some chinks in his armour, but still led the Target World Challenge after Friday's second round.
After building a five-stroke lead, Campbell struggled to complete the second round at even-par 72 for a nine-under total of 133 in the 5.5 million-dollar unofficial event hosted by Tiger Woods.
(USA unless noted):
135 - Michael Campbell (NZ) 63-72
138 - Darren Clarke (NIR) 65-73, Padraig Harrington (IRL) 68-70
139 - Fred Couples 71-68, Kenny Perry 69-70
140 - Chris DiMarco 72-68, Luke Donald (GBR) 72-68, David Howell (GBR) 72-68
141 - Thomas Bjorn (DEN) 70-71, Tim Clark (RSA) 71-70, Jim Furyk 73-68
143 - Davis Love 76-67, David Toms 73-70
144 - Tiger Woods 72-72
145 - Fred Funk 72-73
146 - Colin Montgomerie (GBR) 76-70.