Fishburn, Blair lead PGA Tour's Zurich Classic

At 23-under 193, Fishburn and Blair hold a one-stroke lead over Luke List and Henrik Norlander, with McIlroy and Lowry - tied for top spot after each of the first two rounds - two shots back.

Fishburn and Blair, both winless on the PGA Tour, have been playing golf together since their junior high school days in Ogden, Utah.

"It's why you're out here playing - to have opportunities like this," Blair said.

"I've been out here a handful of years now, so I know they don't come that often. We'll do our best to go take advantage of it."

Fishburn had three birdies and an eagle on the first five holes at wind-swept TPC Louisiana, with gusty conditions also expected for Sunday's alternate-shot finale.

List and Norlander had a 62, with List eagling the second and 11th holes.

"We just got in a really good rhythm early," Norlander said.

"We were both hitting fairways. Not necessarily hitting it really close, but it felt like early we had two chances on every hole."

McIlroy and Lowry shook off a slow start to birdie seven of their last 12 holes.

They shot 64 to join Ryan Brehm and Mark Hubbard, who also had a 64, at 21 under.

"It was a tough day," McIlroy said.

"Birdies were a little harder to come by today than they were on Thursday in the better-ball format.

"Today was about staying patient, knowing the course was going to present some opportunities, especially on that back nine."

Fishburn and Blair were a stroke off the tournament record.

They made the turn in seven-under 29 and birdied five of the first six holes on the back nine before finishing with three pars.

"It's pretty easy to hit shots when Zac is always in the fairway, always on the green," Fishburn said.

"We ham-and-egged it really good today."

Australian Associated Press