Wentworth - Rory McIlroy was kicking himself after carding a first round one-under par 71 as he started the defence of his European PGA Championship title at Wentworth on Thursday.
The world number one was four shots off the early pace set by Sweden's Robert Karlsson, who had a 67, and three away from England's Chris Wood and a pair of Spaniards in Miguel Angel Jimenez and Jorge Campillo who all shot 68s.
McIlroy fresh from his win at Quail Hollow in the United States last week had started with a bogey at the par-4 first and was never better than one-under par and could only manage pars on the two closing par-5s.
"I felt like I left a couple out there but when I look at the leader board I'm only three shots off the lead," the Northern Irishman told reporters.
"Everyone else must have been finding it quite difficult out there, as well. I didn't feel like any aspect of my game was really off today.
"But at the same time, I didn't do anything that good, either. There's definitely room for improvement over the next few days."
McIlroy is following a relentless schedule flying into London from the United States on Monday, attending the European Tour's Players' Awards dinner on Tuesday night and playing Wednesday's Pro-Am with former Manchester United footballers Paul Scholes and Phil Neville.
And the Northern Irishman was aiming to put his feet up after venting his frustrations on the course during his first round.
He added: "Physically I'm all right. Mentally I feel myself getting a bit angry out there which I haven't been doing the last few weeks. I just sort of 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.
"I will try not to do that over the next few days. Just try and get as much rest as I've been getting and I should be okay.
"Mentally, I could feel myself getting a bit down on myself out there. I just need to be aware of that and be conscious that I just need to try to keep everything on an even keel out there."
The Northern Irishman is looking for his fourth title of the year after wins in Dubai and at the WGC Match Play Championship to add to last week's triumph at Charlotte.
Karlsson had two birdies in the last three holes to nip into the lead after Campillo had finished with a flourish, making a birdie four at the 17th and eagling the par-5 18th to build on his encouraging seventh place in last week's Spanish Open.
Another Spaniard, Pablo Larrazabal was a shot back after an opening 69.
Jimenez had a run of three birdies in four holes from the 13th but some big names were struggling on a benign day for golf with Darren Clarke carding a 74 and Padraig Harrington withdrawing after two holes because of shoulder trouble.