Robert MacIntyre and Tommy Fleetwood were three shots off the lead as Russell Henley set the early pace at the Tour Championship in Atlanta.
Henley carded a flawless nine-under-par 61 at East Lake to lead by two from world number one Scottie Scheffler.
Scotland’s MacIntyre and England’s Fleetwood were a shot further back alongside potential American Ryder Cup picks Collin Morikawa, Patrick Cantlay and Justin Thomas.
Rory McIlroy was five strokes off the lead, in a group which also included Sweden’s Ludvig Aberg, after completing a 64 with an unusual birdie in the final group.
His third shot from a bunker on the closing par five came back off a grandstand to the green where he holed from 18 feet, seconds before the siren sounded for the course to be evacuated because of approaching storms.
Rain throughout the day softened the course enough to allow the 30-strong field to clean and place their balls on the fairways.
Henley took full advantage of a day of low scoring, holing three birdie putts from at least 40 feet and closing with three straight birdies.
Scheffler finished with two birdies alongside McIlroy to jump out of the pack as Henley’s nearest challenger.
MacIntyre and Fleetwood came close to winning in the opening two events of the season-ending FedEx play-offs and continued their good form at East Lake.
Fleetwood opened with three birdies, his only blemish coming on the 10th, MacIntyre stringing together three straight birdies from the 11th, with both making a birdie at the last.
