Kevin Stadler carded a five-under-par 67 to share the Houston Open first-round lead with Australian Cameron Percy Thursday. Americans Anthony Kim, Kevin Sutherland, James Driscoll and Vaughn Taylor trailed by a stroke while Phil Mickelson and Padraig Harrington were in a group on 69. Last year's champion Paul Casey was unable to defend his title due to a left shoulder injury. Stadler, whose father Craig won 13 times on the PGA Tour, including the 1982 Masters, said he had hit a rough patch of form recently. “I was fighting my swing the last week or two but I got around today,” Stadler, 30, told reporters. Percy found his putting touch to shoot easily his best score of the year. He credited a lesson on the greens from fellow pro Greg Chalmers' caddie, Malcolm Baker. Ireland's Harrington made a move with three successive birdies from the 14th, before bogeying the last. Mickelson made a sensational birdie at the par-five 8th, despite taking a penalty stroke after pushing his drive into a water hazard. After taking a drop, he hit a hybrid club from 245 yards out and then drained a 50-foot putt for birdie. “It was one of those fluke things,” he said. “I was trying to save par and ended up making a long putt.” Briton Casey said the injury was unrelated to the torn muscles in his rib cage area that kept him out for nearly three months last year. He said his withdrawal was a precaution ahead of next week's U.S. Masters. Fiji's Vijay Singh withdrew after nine holes due to pain in his abdominal muscles. Ochoa rebounds World No. 1 Lorena Ochoa shrugged off a disappointing display at last week's LPGA Tour event by surging into contention for the Kraft Nabisco Championship at Rancho Mirage, California, Thursday. The long-hitting Mexican took advantage of ideal scoring conditions at a sun-splashed Mission Hills Country Club and putted superbly to end the first round of the year's opening major one stroke off the pace. Former champion Ochoa narrowly missed a 10-foot birdie putt on the final green to join Norway's Suzann Pettersen in a tie for the lead but she was otherwise delighted to card a four-under 68. Ochoa, a winner of 27 LPGA Tour titles, finished tied for 52nd at last week's Kia Classic at La Costa, California after closing with scores of 76 and 75. On Thursday, however, she oozed confidence at a venue that ranks among her favourites on the circuit and where she romped to victory by a commanding five shots in 2008. Major titlists Karrie Webb of Australia, Yani Tseng of Taiwan and Karen Stupples of Britain were among a group on 69. Defending champion Brittany Lincicome drained a birdie putt on 12 to get as low as four-under before bogeys at 13 and 15 saw her finish on 70. US star Michelle Wie carded a 71.