Chaska, MN (My Sportsbook) - It took Padraig Harrington most of this season to figure out exactly what he wanted to change in the swing that helped him win three major championships.

Finally over that hurdle, which Harrington says he cleared about six weeks ago, the 37-year-old Irishman is free to concentrate on the second most important aspect of his golf game -- the number next to his name.

"I've got what I need to do in my head clear," Harrington said Thursday after the first round of the PGA Championship, "and once that's clear I'm back thinking about how to perform on the golf course, how to score on the golf course, and that's showing up in my score."

It showed up in the form of a four-under 68 at Hazeltine National, which placed the defending champion just a shot off the early lead held by Tiger Woods.

Harrington, who started on the back nine, rolled in a six-foot birdie putt at the 12th hole and remained under par the rest of his round. He collected five birdies against just one bogey.

Playing alongside Woods -- and Rich Beem, who won the 2002 PGA at Hazeltine -- Harrington found another reason to narrow his focus on the course, besides the newfound comfort level he's enjoying with his re-vamped swing.

"The great thing when you play with Tiger is you know you have to make shots," said Harrington. "You might as well go after it rather than hang back. It helps you focus. You have to be on your very best form and it motivates you."

It marked the second round in a row that Harrington played with Woods.

Their dual at Firestone on Sunday, when Woods came from three back to win the Bridgestone Invitational, created a stir that lasted well into this week. Woods was critical of a rules official who put the pair on the clock at the 16th hole, where a rushed Harrington made a tournament-changing triple-bogey.

Harrington struggled to sleep Sunday night, his collapse on the 16th hole fresh in his mind. But as soon as he started hitting shots at Hazeltine, the feeling melted away.

"That period of time between finishing the tournament and starting the next one sometimes can be quite a tough period," Harrington said. "But you gotta get back out there. When you do, it's pretty easy to focus on going forward."

Lost in the controversy of Woods' comments on Sunday was this startling fact: Harrington's second-place tie marked the first time this season that he posted a top-10 on the PGA Tour.

A two-time British Open champion, Harrington has played the majority of this season not like a three-time major winner, but more like a middling tour pro struggling to make cuts.

In fact, prior to Firestone, Harrington had only made nine cuts in 15 starts this season. He missed three in a row leading up to his title defense at the British Open, where he tied for 65th.

Now free from the constraints that came with adjusting a swing he says had been faulty for 2 1/2 years, Harrington has focused more attention on things like his short game.

And that, he says, has helped him to post low scores like the one he put up on Thursday.

The swing changes he made are not automatic -- Harrington may be done struggling to figure out where he wants to be on impact with the ball, but he's not all the way out of the woods yet.

There are still obstacles to overcome.

"You're not just going to win a major. You're going to find some trouble here and there," confessed Harrington, who at least feels comfortable in the clarity of knowing exactly what he needs to do.

"My mind set is now a lot more at ease," he said.