Jason Day will head into the weekend at the Wells Fargo Championship as a strong favourite after extending his first-round lead to three strokes in Friday's action.

After posting a 63 in much friendlier Thursday conditions, Day was solid again, birdieing two of his first three holes, and was four under through 13. 

After a bogey on 14 and 17, he ended his day on the right foot with a birdie on 18 for a three-under 67, sitting at 10 under through two rounds.

Day, who has not won a PGA Tour event since 2018, told the media after stepping off the 18th green that he is excited to be back in this position after previously spending 51 weeks as the world number one before a number of injuries.

"I'm looking forward to it – it's nice to be back in the mix, nice to be leading," he said. "It's still two more days left, so I can't get too far ahead of myself.

"I mean, not many times you see this hair (after being forced to play without a hat due to the rain), but hopefully this weather can kind of go away and we can have hats on for the weekend.

"When you have conditions like this, it's really hard to commit to a shot because you're going in there and you're doing it kind of a lot quicker than your normal pre-shot routine.

"You have to force yourself to hit the shot and trust that."

Max Homa has a hold of outright second at seven under after posting a 66 – tied for the second-best round of the day. Also shooting 66 was Luke List, who drove the green on the par-four 14th hole to putt in for eagle, flying up the leaderboard into a tie for third at six under.

One shot further back at five under is a small group highlighted by Keegan Bradley, who had the round of the day with seven birdies and two bogeys for his 65.

A strong international contingent is in a tie for 10th at four under, with English duo Tyrrell Hatton and Matt Fitzpatrick, as well as India's Anirban Lahiri and Slovakia's Rory Sabbatini.

Abraham Ancer is part of the group at three under, while some big names are a further shot back, including Tony Finau, Sergio Garcia, Rickie Fowler and Camilo Villegas.

Rory McIlroy, Corey Conners and Matt Kuchar will live to see the weekend after finishing right on the cut line at even par, while Aaron Rai was not so lucky, going from a bogey-free 65 on Thursday to a birdie-free 76, missing the cut at one over.

Also missing the cut was Charl Schwartzel, Francesco Molinari, Marc Leishman and Webb Simpson.