Phil Mickelson finding his form in Texas and just in time for the Masters

Phil Mickelson seems to be rediscovering his form just in time for next week's Masters after finishing the opening round of the Shell Houston Open on Thursday night with a round of 66.

His six under par score has left the 44-year-old American just three shots off clubhouse leader and fellow American Scott Piercy, as he looks to come out of 15 months of wayward form seven days ahead of the same tournament he failed to make the cut for this time last year.

The three time green jacket winner showed no absence of confidence though in equaling his lowest aggregate of the season, the other being the second round of the Humana Challenge in January.

He opened the tournament off on the par-4 10th hole and after missing the green with his approach he had his caddie pull the flag from the hole before settling in with a chipped birdie.

Birdies on the 10th, 12th, 13th, 15th and 17th meant that Mickelson was five under after his outward nine and had a share of the early lead.

Two more birdies on the second and eighth though were blemished by a bogey on the final hole after he found a greenside bunker off the tee at the par -3 ninth.

Three shots ahead of Lefty though and Piercy's bogey-free nine-under-par 63 tied the course record equaling previous scores from Adam Scott, Johnson Wagner, Jimmy Walker and Mickelson himself in 2011.

New European Ryder Cup captain Darren Clarke finished with a round of 71, with bogeys on the 16th and 18th dampening earlier birdies on the second, 13th and 15th. Among the later starters was Padraig Harrington.