CHICAGO • World No. 2 Dustin Johnson, making his case for PGA Player of the Year, birdied four of the last five holes on Saturday to seize a three-stroke lead after the third round of golf's BMW Championship.

The reigning US Open champion sank a 17-foot birdie putt at the 18th hole to complete a four-under 68 and stand on 198 for the tournament at Crooked Stick.

The 32-year-old American, who captured his first Major title in June at Oakmont, sank three birdie putts in a row starting with a 10-footer at the par-four 14th, then a tap-in on the par-five 15th and lastly a seven-footer at the par-four 16th.

"I'm seeing the lines pretty well, I've got pretty good speed and it's going where I'm looking," he said. "I'm making some putts this week."

England's Paul Casey was second on 201 after a bogey-free 68, with American J.B. Holmes (68) third on 202. A course drenched by rain and stirred by winds made it harsh for leaders and rivals alike.

"Really solid. To keep a clean sheet I was really happy," Casey said. "It was pretty ugly. It wasn't my best ball-striking day. The fact I stayed in touch was nice."

Roberto Castro (74), who shared the 36-hole lead with Johnson, fell to fourth on 204, one stroke ahead of US compatriot Matt Kuchar and Australia's Adam Scott.

Johnson opened with a bogey, needing two shots to escape greenside rough, but answered with a four-foot birdie putt at the second hole and closed the front nine with a seven-foot birdie putt. He missed the green at the par-three 13th hole and made bogey, setting the stage for his closing brilliance.

Johnson seeks his third title of the year after the US Open and the World Golf Championships-Bridgestone invitational. It would mark the first season in which he has won three events. A win would also put him atop the FedExCup play-off season points standings in search of the US$10 million (S$13.59 million) bonus paid out after the Tour Championship in two weeks at Atlanta.

AGENCE FRANCE-PRESSE