Lee (three-under 69) and Lowry (six-under 66) have had little previous success at the PGA Tour event at the challenging Bay Hill course in Florida.

"It's not a course where I've played very well so it's quite nice to have my first under-par round and make a few birdies," Perth's Lee said.

"It's where you want to be – the best players in the world are here and I'm proud to be here.

"It's a tough course, I didn't really have that much expectation coming in just because I've nearly come last the last two times I played here."

Lee carded six birdies and three bogeys while countryman and former World No.1 Jason Day also had a rollercoaster round – his two-under featured five birdies and three bogeys.

Fellow Australian Cam Davis posted an even-par 72, while former World No.1s Adam Scott and Rory McIlroy finished one-over on a day when Irishman Lowry finally clicked at Bay Hill.

Lowry's 66 gave him a one-shot lead over American Justin Lower and Japan's Hideki Matsuyama, who were tied for second.

"It's where you want to be – the best players in the world are here and I'm proud to be here.” – Min Woo Lee.

Lowry described his Bay Hill record as "horrific" – in his sixth outing at the tournament, Thursday was the first time he'd broken 70.

"It's one of these places where some people love it but I've struggled with it over the years," he said.

"It's a nice place to come, it's a great tournament, a huge tournament.

"I'm very happy with that today, maybe that's the kind of score I need to shoot around here to just give myself the confidence to go out and play my game.

"This is the type of place where you get on a run and it feels easy.

"But then you get on a run the other way and start making bogeys, it feels like you're never going to make a par out here again."