Shane Lowry made a strong start at the Safeway Open on Thursday, carding an excellent four-under 68 in California.
The Offaly man has opted to contest the first event of the 2020/21 schedule ahead of next week's US Open at Winged Foot.
Lowry will fly straight from the US Open to the Dubai Duty Free Irish Open, which was scheduled for Mount Juliet in May but has been switched to Galgorm Castle in Northern Ireland due to the Covid-19 pandemic and will be played behind closed doors.
The reigning Open champion picked up five birdies and a solitary bogey - on the par-four 13th - to sit five shots off leader Russell Knox in a tie for 21st place.
Seamus Power meanwhile endured a tough first day at the office. The Waterford man is on three-over after going around in 75.
Knox has a one-shot lead after shooting a nine-under 63 on day one of the first event of the new season in California.
The Scot, who missed last season's FedEx Cup play-offs by two spots, had seven birdies and eagled the 550-yard fifth hole before play was suspended due to darkness at the Safeway Open in California.
Australia's Cameron Percy, who had one of three bogeys on the fifth, joined Americans Sam Burns and Brendan Steele a stroke back with a share of second.
Knox, 35, started slowly after hitting his first tee shot into the rough, but built steadily throughout the day after his first birdie on the fourth hole.
After play, he said: "(I) worked as hard as I ever have the last two weeks before this event, so it's really nice to see something good happen immediately. I definitely feel like my game is heading in the right direction."
The tournament takes place in northern California's Napa while much of the US west coast battles wildfires, with players preparing for next week's US Open at Winged Foot in New York.
