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Kuala Lumpur, Malaysia (SportsNetwork.com) - Keegan Bradley shot 6-under-par 66 on Friday to grab a 4-stroke lead at the halfway point of the CIMB Classic.

Bradley, who is making his season debut, sits at 13-under-par 131 through 36 holes on Kuala Lumpur Golf & Country Club's West Course.

"It's challenging, it's very tight and you've got to drive the ball straight," said the former PGA champion. "It's a really good course for me."

Overnight leader Ryan Moore carded an even-par 72 and dropped into second place at 9-under 135, one shot ahead of Chris Stroud and Kiradech Aphibarnrat, who both shot 69.

Sergio Garcia posted a 71 and grabbed a share of fifth place alongside Marc Leishman (65) at 7-under 137.

Phil Mickelson, also making his season debut, is tied for 25th after rounds of 71-70.

"Playing this golf course from the rough, which I did today, is extremely tough," admitted the Open champion.

Moore fired a course-record 63 on Thursday, but he couldn't carry the momentum into the second round, mixing three birdies with a trio of bogeys, which aided Bradley's ascent.

Bradley teed off at the 10th and started slow with a pair of birdies and a bogey over his first nine holes, but he took off after the turn.

The three-time PGA Tour winner birdied two straight from the par-4 second to go in front for good, then built his advantage with a hat trick of birdies from the fifth.

He parred out to retain his 4-shot lead over Moore, who birdied his final hole to partially salvage his round.

"Great tee shot, great iron shot, finally hit a putt exactly how I wanted," Moore said of his closing birdie.

NOTES: Bradley recorded a career-best seven top-10 finishes and finished 10th in the FedExCup standings in 2013 ... With FedExCup points available for the first time at this event, Bradley would earn 500 points with a victory ... Defending champion Nick Watney is tied for 42nd place at even-par 144.