PGA Tour: Justin Thomas in hot pursuit of Sahith Theegala at Fortinet Championship

A 65 left the double major winner two shots behind Sahith Theegala, two ahead of Australian Cam Davis – who matched Thomas' 65 – and SH Kim of South Korea.

"To get a win in the home state would mean the world," said Theegala before acknowledging that maybe he is feeling some pressure after all.

"I'm sure I'm going to be very nervous, but just going to channel those nerves and try and have fun."

Matt Kuchar also shot 65 around the Silverado Resort at Napa, California, and is a shot further back alongside fellow American Eric Cole.

Former world number one Thomas relied on a wildcard pick to make the US team to face Europe after a torrid season.

Three rounds in the 60s, helped by holing out from a bunker for an eagle on the 15th, have put him in contention for a first PGA Tour win of the year – less than two weeks ahead of the showdown in Rome – but he still felt it could have been better.

He said: "I felt I was not very sharp today in terms of my actual golf game. Being in contention with the golf I've had this week is more encouraging than anything."

Fellow Ryder Cup player Max Homa, winner for the past two years, fired a third-round 70 to lie seven shots adrift heading into the final round.

"Winning the golf tournament is starting to feel a little bit fleeting," said Homa.

"Should be a good event. Hopefully I can maybe make some noise."

READ MORE: BMW PGA Championship - Ludwig Aberg moves two shots clear as he chases consecutive victories