His major streak may have been extended to five years at The Open but Rory McIlroy birdied four of his last five holes in a stunning round of 62 to open up a one-shot lead heading into the final round of the WGC-FedEx St. Jude Invitational.

The Northern Irishman entered the day at TPC Southwind five shots off the lead but carded his lowest ever round in a World Golf Championships event and his lowest of the season on the European Tour to get to 12 under par and lead the way from World Number One Brooks Koepka.

The two four-time Major champions will now go out in the final group on Sunday in what promises to be a scintillating final day as the tournament makes its first appearance in Tennessee.

McIlroy won this event in 2014 when it was played at Firestone Country Club and will be looking for a third World Golf Championships win, while Koepka will be seeking his first, as will overnight leader Matt Fitzpatrick of England.

The Englishman carded a round of 69 to sit in third place at ten under par, a shot clear of Swede Alex Noren, Spaniard Jon Rahm and Australia's Marc Leishman.

American Billy Horschel, Dane Thorbjørn Olesen, and Ian Poulter of England are then at eight under par, while his countryman Tommy Fleetwood is in a tie for tenth place alongside American trio Webb Simpson, Justin Thomas and Bubba Watson at seven under par.

"I had a goal in my head, I wanted to get to double digits under par by the end of the day, and obviously I did a little bit better than that," McIlroy said. "Made a nice run at the end there and obviously in a good position heading into tomorrow.

"It is exciting. Brooks is the number one player in the world, four majors in the last three years. He's the man right now. I got to play with him the first couple days, and I enjoyed it. I enjoyed seeing what he can do.

"I think you learn way more from your failures than you do from your successes. Any time I have an undesirable week, I really look at it, and I try to examine what went wrong here and what can I do to put it right the next week.

"The great thing about golf, it provides you opportunities all the time. You miss a cut, you can get straight back on the horse the next week and try again. Not a lot of sports have that luxury. I think we're very fortunate that we can try to respond to our setbacks pretty quickly."

Koepka's world number one ranking is safe this week, but he's looking forward to a clash with McIlroy, who can move ahead of Dustin Johnson to second.

"I feel like I putted really good the last couple weeks and nothing's fallen in and today they finally fell," Koepka said. "I played really solid, felt like I didn't make too many mistakes. Got a little loose with the driver there and just kind of under it a little bit, that's why they're leaking to the right. But overall, I have no complaints today.

"It will be fun. Rory's playing some good golf, especially with the start he got off to. Played with him the first two days. The way he struck it was really impressive. He's putting well, and you know he's going to be tough to beat."