cool Zach Johnson held off late challenges by fellow Americans David Toms and Charles Howell III to win the Sony Open by two shots on Sunday. One ahead at the start of a breezy day of sunshine at Waialae Country Club, Johnson birdied four of the last nine holes for a five-under-par 65 and his fifth PGA Tour title. Although the former US Masters champion squandered a three-stroke advantage early in the final round, he responded with timely birdies at the 11th and 14th en route to a 15-under total of 265. Toms closed with a five-birdie 66 to share second place with Australian Adam Scott, who covered the back nine in five under for a sparkling 64. Howell birdied 16 and 17 to hold a brief share of the lead before bogeying the last for a 66 and fourth place at 12 under. Johnson made a fast start with a birdie at the opening hole and forged three ahead before being caught by Toms and Howell by the turn. He briefly regained the outright lead by coaxing in a 16-footer for birdie at the par-four 10th before playing partner Toms matched him with a 10-foot putt at the same hole. However, Johnson again took control, rolling in a seven-footer at the par-four 11th to edge one ahead at 13 under. Howell, having chipped in for birdie at the par-four 16th, drew level with Johnson after sinking a 22-footer at the par-three 17th. Again Johnson responded, a precise approach to 10 feet at the par-four 14th setting up his sixth birdie of the round and a one-stroke advantage at 14 under. Toms moved into a tie for second at 13 under. A perfectly placed drive at the par-five 18th, followed by a three-wood to 35 feet, set up a two-putt birdie for Johnson to sign off in style.