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Chris Kirk was feeling burned out just three months into his first year on the PGA Tour.

He changed drivers and irons, and feels a lot better about things after two rounds at the Houston Open.

The PGA Tour rookie shot a 3-under 69 on Friday to take a one-stroke lead over defending champion Anthony Kim and 2008 winner Johnson Wagner.

Kirk has carded his first two sub-70 rounds since mid-February at the Tournament Course at Redstone to reach 9-under par. He missed four cuts in his previous five starts and conceded that he wasn't motivated to turn things around.

"Just was kind of in a little bit of a funk," he said. "I don't really feel like I was playing that bad of golf. I just lost interest somehow."

He rekindled his intensity with the equipment change this week, and opened with a 66 on Thursday. He then birdied two of his last three holes Friday to take the outright lead and make up for a double bogey on the par-5 4th.

"Golf is such a frustrating game, and you have a couple of weeks like I did the last few weeks, and you feel like you don't know how to play anymore," he said. "And then, as soon as that happens, you play a round like I did (Thursday) and just, I don't know. It's a crazy game, that's for sure."

Padraig Harrington, first-round leader Jimmy Walker and Josh Teater were two shots back at 7 under.

Organizers groomed the Tournament Course at Redstone to simulate conditions that players will see at the Masters next week, and the setup lured many of the world's top players to Houston.

Phil Mickelson (70) and Lee Westwood (72) were part of a large group at 4 under and Ernie Els (72) and Fred Couples (72) were among the players at 1 under.

Kim shot a 64, the lowest round of the day and four strokes better than his lowest round when he won last year. He's trying to become the first back-to-back winner of the event since Vijay Singh won in 2004 and '05, the last two years it was played at the adjacent members' course.

Starting on the back nine Friday, Kim made six birdies in his first 10 holes, including chip-ins on Nos. 12 and 16. He needed only 22 putts to equal his lowest round since January.

Kim said before the tournament that his swing needed major retooling and that he spent several days working with coach Adam Schreiber on changes. Kim's gratified that the work is already producing results.

"It feels great to have that feeling of confidence and go out there, make some good golf swings and make a couple of putts after that," Kim said.

Kirk has some background at Redstone, too. He played for Georgia and competed in the same collegiate event that Kim won here in 2006.

"I think he likes this course," Kirk said. "I shot a bunch of 74s, or so, nothing very memorable."

Wagner feels a more emotional connection to Redstone after earning his first tour victory here three years ago. He needs to win this week to qualify for the Masters, but said next week's major has hardly crossed his mind.

A Charlotte resident, Wagner ranks the tournament at Quail Hollow near his home and the Houston event as important as any he plays all year.

"There are a few regular tour events that I treat as a major," he said. "Houston and Charlotte will always be my two favorite events that we play."

Harrington seems to like it, too. He has played here every year since the event moved to the Tournament Course at Redstone and finished in the top 40 each time.

He opened with a 68 on Thursday, then birdied two of his first three holes in the placid morning conditions Friday. Also starting on the back nine, he hit his tee shot into the bunker on the par-3 14th and bogeyed, but then holed birdie putts on 16 and 17 to reach 8 under.

Harrington dropped back with three straight bogeys on his back nine, then reached the par-5 8th in two shots to set up an eagle to get back to 7 under.

"I just fell asleep there," said Harrington, sporting a beard this weekend because he forgot to pack a razor. "I really kind of battened down the hatches for the last couple of holes, trying to not make too many mistakes after I lost my way."

Former President George H.W. Bush watched the early rounds from a golf cart and greeted Mickelson and Couples as they walked off greens. Bush regularly attends major sporting events in Houston, where he lives.