FORT WORTH (AP) — Tim Clark had the perfect remedy to overcome a stiff neck and an extended day of golf: anti-inflammatory medicine and a steady dose of fairways and greens.

Clark had to play the back nine of his opening round Friday, then got only a brief break before a bogey-free 6-under 64 in a second round in which he didn’t miss a fairway or a green.

“It certainly makes it easier to get around,” said Clark, who at 11 under had a one-stroke lead over Arron Oberholser (66) in the rain-soaked Colonial.

“This could be my last week for a while. I’m going to take some time off to heal up. I want to end on a good note.”

The South African was among 57 players — exactly half the 114-player Crowne Plaza Invitational at Colonial field — who had to finish their first rounds Friday morning and then go right back out for 18 more holes.

The 36-hole cut, projected to be under par for the first time in the 61 years at Colonial, won’t be made until the second round is completed Saturday morning. There were 27 players still on the course when play was suspended Friday because of darkness.

Ben Curtis (67), Jim Furyk (66) and Nathan Green (66) were in at 9-under 131, with Alex Cejka (65), Kevin Na (69) and first-round leader Anthony Kim (69) at 8 under.

Clark’s 11-under 129 total was only one shot off the 36-hole tournament record held by Kenny Perry.