Americans Matt Bettencourt and Peter Tomasulo share a one-shot lead after the first round of the Texas Open on Thursday, while several Australians are in contention. Bettencourt, 37, holed six birdies and a bogey at the TPC San Antonio, while Tomasulo went through bogey free as their five-under 67s gave them a narrow advantage. Irishman Padraig Harrington shares second with Americans Billy Horschel, Bryce Molder and Harris English joining him on four under. World number two Rory McIlroy, looking to sharpen his game ahead of The Masters, carded an even-par 72 to be tied for 45th. A group of 10 players are locked on three under in a tie for seventh, including American Jim Furyk and Englishman Brian Davis. Australians Nathan Green, Alistair Presnell and Steven Bowditch are among those on three under. Rod Pampling (one under) and Greg Chalmers and Cameron Percy (even) also made decent starts to the tournament. Bettencourt made the perfect start in Texas – on what is considered one of the toughest courses on the PGA Tour – birdying the par-four 1st hole. The one-time winner on the PGA Tour followed that up with birdies on the 3rd and 5th, but he also bogeyed the par-four 4th. Bettencourt was consistent on the back nine, holing three birdies as he finished strongly, while Tomasulo joined him in a share of the lead after birdies on the 17th and 18th holes. Harrington would have joined the leaders, but a bogey – his only one of the round – at the par-five 18th was costly. Horschel and Molder mixed six birdies with two bogeys, while English strung together a rollercoaster round that featured five birdies, three bogeys and an eagle. McIlroy continues to struggle ahead of the year&aposs first major, holing four birdies and as many bogeys during his round. Defending champion Ben Curtis produced a two-over 74 to be well back in a tie for 76th.