Former British Open champion Louis Oosthuizen birdied five of the last seven holes to charge two shots clear in the third round of the weather-delayed Houston Open Saturday. The smooth-swinging South African recovered from bogeys on the first two holes to card a six-under-par 66 at the rain-softened Redstone Golf Club in the final PGA Tour event before next week's Masters. Oosthuizen, who romped to a seven-stroke victory at the 2010 British Open, launched his late surge with four consecutive birdies from the 12th to post a 17-under total of 199. American Hunter Mahan was alone in second place after carding a 65, with Swede Carl Pettersson (67) and Britain's Brian Davis (69) a further stroke back at 14-under. For the second round in a row at Redstone, players were permitted to lift, clean and replace their balls on a course that had been saturated by more than an inch of rain on Thursday. Asked how he would approach Sunday's final round, Oostuizen replied with a smile: “Pretty much the same as today, try and not start bogey-bogey. Defending champion Phil Mickelson was among a group of three players tied for sixth at 11-under after shooting a three-birdie 70. Three-times major winner Ernie Els, who needs to win the Houston Open to qualify for next week's Masters, was at eight-under 209 after shooting a second successive 69. Earlier in the day, American Jeff Maggert birdied three of his last eight holes to grab a one-shot lead when the weather-delayed second round was finally completed at Redstone to get the tournament back on track. The 48-year-old went on to shoot 76 in the third round to finish a long day tied for 14th at eight under par. Sjodin joins Tseng atop In Rancho Mirage, California, Sweden's Karin Sjodin steered a steady course in gusting winds Saturday, firing a four-under 68 to join world No. 1 Yani Tseng atop the Kraft Nabisco Championship leaderboard. Sjodin, who is seeking a first victory in seven seasons on the LPGA tour, had just one bogey as she joined Tseng on nine-under 207 going into Sunday's final round of the first women's major of the year. Tseng, a five-time major champion, is currently the dominant force in the women's game. But she showed some frustration on her way to a one-under 71 at Mission Hills. South Korea's Haeji Kang, also seeking a first LPGA Tour title, was two strokes back after struggling to a 72. World No. 2 Na Yeon Choi of South Korea led a group of five players on six-under.