American golfer Keegan Bradley seized a four-shot lead on day two of the CIMB Classic in Malaysia on Friday as a struggling Phil Mickelson conceded his swing was in line for off-season repairs.

Bradley, the 2011 PGA Champion, moved to 13-under-par 131 for the $US7 million ($A7.3 million) tournament at Kuala Lumpur Golf and Country Club, overtaking first-round leader and countryman Ryan Moore.

Moore was second at nine-under (135) after an even-par 72.

Australian Marc Leishman is in contention after rounds of 72 and 65 to be equal fifth with Spaniard Sergio Garcia on 137 – one shot behind Thailand’s Kiradech Aphibarnat and another American Chris Stroud, who are tied for third on 136.

Fellow Australian Wade Ormsby is two strokes adrift of Leishman Garcia on 139, with Aaron Baddeley just one further back.

Halfway leader Bradley said he was having a blast playing “some of the best golf I’ve played in a long time”.

“I’m in a great spot with two rounds to go. Every hole out there, you can make a bogey. There is no easy hole,” said Bradley, ranked 15th in the world.

“I got to keep playing aggressively and shoot a good round the next two days.”

A day after complaining that he played some of his worst recent golf in round one, world No.3 and reigning British Open champion Mickelson said he was “not much better today” as he carded a two-under 70.

That left him 10 shots off the pace and tied for 24th at three-under.

“I don’t have control of the swing,” he said.

“You need to be in control in this golf course as the rough here is very tough.

“My rhythm is better but, technically, there are still many issues to address. It’s going to be tough this week and next and I will probably focus on fixing (the swing) in the off-season.”

Mickelson is heading a bumper field at the CIMB Classic, which this year becomes the first PGA Tour event in Asia to offer points for the FedExCup championship that culminates each year in September.