Rickie Fowler put together a four-under 68 to capture the outright lead at the Wells Fargo Championship.

The American started the day at an unassuming pace with pars on his first seven holes before getting birdies on holes eight and nine. He made the turn and birdied 10 to move to eight under, but dropped strokes on holes 11 and 13 to take the air out of his following.

However, Fowler caught a second wind with birdies on 14, 15 and 16 to jump into a share of the lead with Roberto Castro at nine under before scoring pars on 17 and 18. 

"Main thing was just to go out and make sure I was in position to win tomorrow," Fowler said.

"I didn't want to take myself out of the tournament. So whether it was out in front by a few shots or tied for the lead or a shot or two back, I just didn't want to be out of position."

Saturday was Fowler's second consecutive four-under round as he seems to be one of the more comfortable golfers on the course.

He has 15 birdies over three days, which is second to Justin Rose, who sits in a tie for third place at seven under, alongside James Hahn (68).

A win on Sunday would certainly give Fowler momentum as he heads into The Players Championship next weekend to defend his second and most recent PGA Tour title.

"From about a year ago to two years ago to where I'm at right now, whether it's being in the final group or having a chance to win, being in contention, it's completely different,” Fowler said.

"You know, it was I would say before maybe not the complete belief or knowledge of knowing what to do and how to win to get the job done, but now it's fun to go out there and go take care of business.”

Fowler will be paired with Castro (eight under) on Sunday.

Northern Irish defending champion Rory McIlroy continued to struggle, a 73 seeing him sit in a tie for 19th along with Adam Scott.