WGC - Bridgestone Invitational update:Pádraig Harrington finally dialed into the sort of form that won him three majors in little over 13 months by moving into a share of the lead on the opening day of the WGC-Bridgestone Invitational at Firestone Country Club in Akron, Ohio.

The Dubliner was the model of consistency as he plotted his way round Firestone and took his opportunities as they came along.

Having set off from the 10th Harrington immediately moved under par with a birdie at his opening hole. A second birdie at the par five 16th came before turning in 33.

The front nine got even better as he started with back-to-back birdies at the first and second. With four remaining Harrington was four-under and in share of the lead alongside Thailand's Prayad Marksaeng and South Africa’s Tim Clarke who both carded 66s.

Marksaeng opened with three birdies in a row, starting from the 10th tee on the tough, 7,400-yard, par-70 South Course, but closed bogey, bogey on the way to a seven-birdie, three-bogey 66.

That gave him the early clubhouse lead at four under par, where he was joined by Clark, whose 66 featured six birdies and two bogeys.

Darren Clarke promised plenty during his round bu eventually had to settle for an opening one-over 71.

Graeme McDowell, Rory McIlroy and Shane Lowry were all on the wrong side of par as they struggled to keep bogeys off the card.

McDowell started at the 10th before proceeding to rack up six bogeys and just three birdies for an opening three-over 73. That was two better than Rory McIlroy, whose 75 contained seven bogeys and two birdies.

Lowry, playing his first professional tournament in the States and only his seventh in all since winning the Irish Open in May, looked somewhat out of his depth as he signed for a 78 as nine bogeys littered his card with a solitary birdie coming at the third.

There was better news for Pádraig Harrington and Darren Clarke with the former one-under through six, while the latter was level par after 10 holes.

A 67 from American Steve Stricker left him a shot behind Marksaeng and Clark while there were 68s from US Ryder Cup star Hunter Mahan, Australian Robert Allenby and Spain’s Miguel Angel Jimenez.

British Open champion Stewart Cink and England’s Ian Poulter were among a group of late starters quickly moving to two-under.

Cink, playing for the first time since defeating Tom Watson in a play-off at Turnberry last month to claim his first major victory, birdied the first two holes and was two-under after six.

Poulter, meanwhile, birdied the second and third holes and was two under after four.

US Open champion Lucas Glover, Players champion Henrik Stenson and two-time PGA Tour winner this year Kenny Perry were among those in the clubhouse with 69s while Lee Westwood, a joint runner-up here last year, six-time winner Tiger Woods all reached one-under early in their rounds.

Defending champion Vijay Singh, world number two Phil Mickelson and Masters champion Angel Cabrera were in a large group that posted level-par 70s.

Mickelson, returning to golf after taking six weeks off to care for his wife Amy as she began treatment for breast cancer, showed some rust with a double-bogey six at his second hole of the day, the 11th, and went out in a three-over 38, only to claw his way back with three birdies on the back nine.

Also at level par were England’s Luke Donald and Ross Fisher. Fisher admitted he had come into the tournament short of practice following the birth of his first child, Eve Rose, who was born the Saturday after he had contended on the final day of last month’s Open.

“I’ve hardly played at all to be honest,” Fisher said. “I had two days of practice at home so I’m not as tournament-prepared as I would have liked to have been, but obviously circumstances have changed at home so that is the way it is at the moment.

“It was a decent start but it was a bit frustrating.

“I felt like I played really well for my front nine but just couldn’t get anything going on the greens, didn’t hole anything.

“Then I hooked a drive up the first almost in the water and hit a shocking three-wood into the second and I walked off with a par and a birdie.

“So it was a little bit of a strange day to be honest but level par is a decent start.”