Tiger Woods is the leader in the clubhouse on five under par at the USPGA at Hazeltine golf club, with Padraig Harrington one shot behind him after Thursday's play on four under par.

The two picked up where they left off last Sunday, when the two dueled on the final pairing at Firestone for the WGC-Bridgestone Invitational,  and both played stellar rounds of golf.

Harrington started with his only bogey of the day but quickly rebounded with consecutive birdies on holes 2 and 3. Three more birdies over his round left him in great shape at four under, right behind Woods, who shot a bogey-free round peppered with five birdies.  

"The great thing when you play with Tiger is that you know you're going to have to play the shots," Harrington said.

"It puts you under more pressure and you feel like you might as well go after it rather than hang back.

"It actually helps you focus and you know you have to be on your very best form. It motivates you to play well."

Graeme McDowell shot a two under par 70, while Rory McIlroy shot a one under par 71. Darren Clarke had a tough round and carded a six over par 78.