PGA Championship: Rory McIlroy shows anger as Molinari leads

Rory McIlroy is attempting to win a third title in four events

Rory McIlroy says he is fighting to keep his emotions in check after getting "a little angry" during his BMW PGA Championship opening round.

The defending champion, who threw his club in frustration, is six shots behind leader Francesco Molinari at Wentworth.

"Physically I am all right but mentally I could feel myself getting a little angry out there," said the 26-year-old.

Italy's Molinari leads by two shots after a seven-under-par 65.

World number one McIlroy, who won his 11th PGA Tour title in the United States at the Wells Fargo Championship last week, hit three bogeys in a round of 71 despite perfect conditions.

He faces a fine from the European Tour after throwing a club following a poor second shot to the 17th.

It is not the first time this season McIlroy has been in trouble for such an incident, with the world number one throwing his three iron into a lake at Doral during the WGC-Cadillac Championship in March.

He has also thrown a club at Wentworth before, doing so in 2012 on his way to rounds of 74 and 79.

"Acceptance of bad shots is the thing I have been doing so well and I feel like my patience was wearing a bit thin today," said the Northern Irishman.

"I just need to stay in control of my emotions because I feel like that's one of the things - if I'm a little tired or a little fatigued mentally - I'll start to be hard on myself and start to get down on myself."

Francesco Molinari has just one top-10 finish in 10 starts on the PGA Tour this season

Molinari, whose brother Edoardo retired with a wrist injury during the first round, hit seven birdies including two on the final two holes.

"I think I missed one green on the third and chipped up to two feet, so it was as stress-free as it could be round here," said the 32-year-old.

"I love this place and it's good to be back. It rewards accuracy, which suits my game."

Sweden's Robert Karlsson is two shots off the lead with Britons Chris Wood and Marc Warren a further shot back.

Wood, who dropped just one shot - on the par-five 17th, has played just six events this season after five months out with a broken bone in his wrist.

"It was a nightmare because I fell out of the top 60 on the Race to Dubai and plummeted down the world rankings," said the 28-year-old.

Ireland's Padraig Harrington pulled out with a shoulder injury after playing just two holes.