The Northern Irishman will hope he gets as lucky with the weather as he did on Saturday as gale-force winds and driving rain blew many of his potential rivals out of contention, only for balmy conditions to take over a third of the way through his round.
Clarke, 42, tied for second in the 1997 British Open and tied third in 2001 but has not managed a top-10 finish in any major since.
Should he go on to win on Sunday, becoming the 12th different winner of the last 12 majors, he will be the third Northern Irishman to win one of the sport’s flagship events in 14 months following the back-to-back US Open triumphs of Graeme McDowell and Rory McIlroy.
Clarke will go out last at 13.10GMT with Dustin Johnson, who shot an impressive 68 on Saturday as he too seeks a debut major and a first in six for America.
Rickie Fowler and Thomas Bjorn are a further two shots back on two-under par, Miguel Angel Jimenez and Lucas Glover are on one-under ahead of a group of six, including Phil Mickelson, on level par.
The weather is predicted to be windy and rainy, though not as bad as on Saturday, gradually clearing later in the afternoon when the last few groups should be turning for home.
