Britain's Lee Westwood, the 18-hole Masters leader seeking his first major title in 55 attempts, opened his second round on Friday with a par to remain atop the Augusta National leaderboard.
World No. 3 Westwood has finished in the top three in five of his past nine major starts and the 38-year-old Englishman hopes his strong iron play will bring victory on a course where approach shots are often the key to winning.
"I came close recently and I have had a good career and all there is to win is a major championship and that is my primary focus now," Westwood said.
Westwood ran off four birdies in a row in a front-nine stretch Thursday in a five-under par 67 round to take a one-stroke lead over Sweden's Peter Hanson and South African Louis Oosthuizen, the 2010 British Open champion.
Cold and overcast conditions greeted players Friday morning on a rain-soaked layout that offered many mud balls.
Westwood started in the 11th group and stayed on five-under after the par-4 first with Hanson and Americans Ben Crane and Jason Dufner, early starters who birded the par-5 second, one stroke back.
American Zach Johnson, the 2007 Masters champion, birdied two of the first three holes to move two strokes off the lead.
Oosthuizen, who birdied four of the last five holes on Thursday, took a double bogey at the second, answered with a birdie at the third but stumbled back with bogeys at the fourth and fifth, falling four shots off the pace.
The chasing pack
World No. 2 Rory McIlroy, the 22-year-old Northern Irishman tabbed as a Masters favorite after a back-nine Sunday nightmare cost him last year's green jacket, also has a morning start. The reigning US Open champion opened on 71.
Tiger Woods, the 14-time major champion chasing the record 18 majors won by Jack Nicklaus, opened with a 72 and will play in the day's penultimate group. He struggled off the tee on Thursday in his first competitive round since snapping a 28-month win drought last month at the Arnold Palmer Invitational. World No. 1 Luke Donald of England will be in Friday's last group after opening with a 75.