NORTHERN IRELAND’S Graeme McDowell was left to rue a poor start and finish to an opening round, two under par 70 – five shots behind early leaders Carl Pettersson and Angel Cabrera – in the weather-interrupted Houston Open at Redstone Golf Club in Texas.

In the final event before next week’s US Masters at Augusta National GC, McDowell was looking to build on his excellent form of late.

Having started on the 10th tee, he suffered a double bogey at the par four 12th but demonstrated his mettle with birdies on the 15th and 18th to turn in level par 36.

He continued that momentum with a hat-trick of birdies from the fourth to the six holes to move to three under for the tournament, holing from 16 feet, 11 feet and six feet.

However, the par five eighth, his 17th hole. was to prove something of a card wrecker. He hit a relatively short tee shot, and then pushed his second short right into a bunker.

From there he thinned it across the green and into the water on the far side. Having taken a penalty drop, he chipped to six and a half feet, holing well to drop just the one shot.

On his final hole, the 209-yard, par three, ninth, he found the middle of the green with his tee shot, 34 feet from the pin. His first putt finished about two and a half feet short of the cup and he tidied up to complete his round with possibly mixed feelings.

Pettersson rebounded from missed cuts in his last two PGA Tour starts by charging into an early tie for the lead. The 34-year-old Swede, putting superbly on the slick greens, birdied five of his first eight holes on the way to a five-under-par 67 in the final tune-up event before next week’s Masters.

Pettersson, a four-times champion on the US circuit, briefly got to eight under but bogeyed the par-four 17th before finishing level with long-hitting Angel Cabrera of Argentina.

Americans Ricky Barnes and Jeff Maggert were a further stroke back after opening with 66 before play was suspended due to the threat of lightning in the area.

Pettersson, who reached the turn in five-under 31, was delighted with his score after missing successive cuts at the Transitions Championship and last weeks Arnold Palmer Invitational.

“I got off to a great start . . . kept it going and got it to eight under.

“It was a little disappointing bogeying 17, but I gave myself a great chance on 18 and didnt make it. I’m happy with seven under. I played really good, solid from the tee, hit good irons and putted really well.”

Asked what had made the difference following his two missed cuts, Pettersson replied: “I changed my set-up. I opened up my stance and enabled my left hip to really fire through the ball. I play my best when my club really exits left through the ball.”

World number three Lee Westwood and fifth-ranked American Steve Stricker each carded 68 while US Ryder Cup player Hunter Mahan opened with a 69.

Padraig Harrington and Darren Clarke were among the late starters, as was Masters champion Phil Mickelson, who won last year’s event by three shots.