THIRD-ROUND LEADERBOARD -14: D Clarke (NI) -13 M Campbell (NZ), P Harrington (Ire) Selected others: -8: L Donald (Eng) -3 T Woods (US), D Howell (Eng) -1 C Montgomerie (Sco)

Clarke is 14 under par, one shot clear of overnight leader Michael Campbell (68) and Padraig Harrington (65).

Luke Donald is six off the pace after a 68 while tournament host Tiger Woods is 11 back after a 69.

"I played pretty well after making bogey at the first and gave myself a lot of chances," said Clarke.

"I got another couple of eagles, which covers up a few mistakes."

Clarke attributed his success this week to a "lack of beer", adding: "I could give you a diplomatic answer, but I prefer to give you the truth."

He explained that this week is usually one of rest and relaxation and, even when he plays in this exclusive event, he enjoys it "more off the course than on the course".

But he concluded that after opening with a 65 on Thursday it had "wrecked my plans for the whole week".

Harrington birdied the last and signed for a 65, with Kenny Perry in fourth at 11 under after carding a 66.

"It can be quite a frustrating golf course," Harrington said. "One of my strengths is to stay patient, and that's probably why I have performed well here in the past."

Woods had his best round of the week but looks set to finish outside the top two for the first time since 1999.

"Realistically, it's been a long season, and this week I just haven't capitalised on my opportunities," said the world number one.