Wyndham Clark produced a spectacular 65 on Saturday to storm into a five-stroke lead at the BMW Championship, recovering brilliantly from a double bogey on the opening hole.

Starting the third round just one shot clear of the chasing pack, Clark put together six birdies and an eagle at Bellerive Country Club in St. Louis, Missouri, to move to 17-under par.

The two-time US Open champion will head into Sunday’s final round alongside Rory McIlroy, who sits five strokes behind on 12-under.

“Overall, awesome day,” Clark said after matching the best round of the day.

His remarkable performance was even more impressive considering the way his round began. After two bogey-free rounds, the overnight leader attempted an ambitious shot from the edge of a fairway bunker and misjudged his approach, resulting in a double bogey at the first.

“It was an unfortunate break… probably should have just chipped out and played for bogey,” Clark admitted.

He quickly recovered, pulling level with Gary Woodland after his birdie putt on the fourth hole narrowly dropped. Clark then produced an excellent wedge from deep rough to birdie the seventh.

The American extended his advantage with a stunning eagle at the eighth, hitting a precise iron shot before rolling in a 12-foot putt to establish a three-shot cushion.

Clark then took complete control on the back nine, adding birdies at the 10th, 11th, 13th and 14th holes, including a brilliant 30-foot putt at the 10th.

He produced an important 15-foot par save at the 16th but missed a short birdie opportunity on 17 before dropping another shot at the final hole.

“I got into a great groove and played amazing. I’m just a little bummed right now at how I finished on 17, 18,” Clark said.

While Woodland struggled to keep pace, Rory McIlroy surged into second place with a lively 65 of his own.

The Northern Irishman found only four fairways during his round but still managed to stay in contention. He birdied the par-three third before recovering from a wayward drive at the eighth, somehow sending his second shot through both a tree and a bunker to make par.

McIlroy then accelerated on the back nine, producing five birdies, including a 26-foot putt on the 16th, to cut into Clark’s advantage.

“Playing this golf course from the rough isn’t fun. But I hung in there. My short game saved me a couple of times,” McIlroy said.

“I’m in a good spot going into tomorrow in terms of where I’m at on the leaderboard. But it’s going to take a heroic effort from one of us to catch Wyndham.”

McIlroy added: “I think you can be aggressive here.”

He was joined in second place by Patrick Cantlay, who finished with a birdie at the 18th to card a 66.

Woodland and Chris Gotterup sit another shot back at 11-under, with Collin Morikawa also in the chasing pack.

The BMW Championship is particularly important for Woodland and Cantlay, who are both battling to secure their places in the 30-player field for next week’s season-ending Tour Championship in Atlanta.

World number one Scottie Scheffler, who had recovered strongly on Friday after struggling with illness during the opening round, also made progress early on Saturday, reaching six-under par.

However, Scheffler gave two shots back with back-nine bogeys as his hopes of mounting an unlikely comeback faded.

He eventually finished the third round at five-under par after a 68.