Australian rookie Marc Leishman is well in the hunt for a maiden PGA Tour victory after a weather-delayed third round at the Texas Open. Threats of lightning in San Antonio brought play to a halt for almost five hours, leaving the top 24 players on the halfway leaderboard to wait until late afternoon to start their rounds. Leishman had five birdies and just one bogey through 17 holes before play was suspended due to darkness. The Victorian finds himself in a tie for fourth place at 11-under-par, four shots behind clubhouse leader Zach Johnson, who fired a superb 10-under-par 60. The long wait did little to upset former Master champion Johnson, though, as he moved from five under par for the week at the par-70, 6,896-yard Resort Course to take the overnight lead at 15-under after equalling the course record with an eight-birdie, one eagle round. After a front nine of 30, the highlight of which was the two he scored at the par-four seventh, holing out from 84 yards, the American shot five birdies after the turn and as darkness descended Johnson gave himself an shot at a round of 59 with a 20-foot birdie putt at the 18th. The putt came up short and the second 60 of his career went into the books instead. Not only that, but by finishing before play was suspended due to the fading light, the 2007 Masters champion also gave himself a lie-in on Sunday while his rivals will be returning to the course to complete their third rounds. Johnson has a three-shot lead over halfway leader Paul Goydos and first-round co-leader Justin Leonard, who were called in having played 12 holes. James Nitties is the next best Australian after Leishman in 21st place at seven-under, while Nathan Green and Aron Price are tied for 42nd. Greg Chalmers and Matt Jones are languishing down the wrong end of the leaderboard in 50th and 68th position respectively. Meanwhile, amateur Shane Lowry, playing what Colin Montgomerie called &aposincredible&apos golf, continued to live in a dream world at The Irish Open at County Louth – and is joint leader with England&aposs Robert Rock heading into the final round. Not even a five-hour hold-up for strong winds rattled the burly 22-year-old off track in what could now become the most astonishing European Tour debut in history. Brett Rumford is the best placed Australian at five-under par, some 11 strokes off the lead.