Luke Donald faces a battle to hold on to his world No 1 ranking after a poor first round in South Carolina. The Englishman needs a top-eight finish at the RBC Heritage at Hilton Head to stay above Rory McIlroy at the top of the standings.
Donald is eight shots behind the first-round leaders, Chad Campbell, Vaughn Taylor and Colt Knost of the USA.
Starting at the 10th hole in windswept conditions, Donald made three bogeys and one double-bogey in his four-over-par 75. The 34-year-old Englishman spent 40 weeks at No 1 before being replaced, for two weeks, by Northern Ireland's McIlroy in March.