England's Paul Casey will head into the final round of the Deutsche Bank Championship with a three-shot lead after carding a third straight 66 on Sunday.
Casey, who started Sunday's third round one shot behind leader Kevin Chappell at TPC Boston, was one under through four after a bogey on three, but reeled off three birdies in a row from the fifth and added another on 16 before closing with a brilliant eagle at the par-five 18th.
Brian Harman was second on 12 under after a 68, with Chappell (71), USPGA champion Jimmy Walker (70) and Smylie Kaufman (68) tied for third a stroke further back, and first-round co-leader Ryan Moore (68) sixth.
Northern Ireland's Rory McIlroy (66) and England's Justin Rose (69) were nine under alongside former Open champion Louis Oosthuizen and Tony Finau in the second of four season-ending FedEx Cup play-off events.
McIlroy, not for the first time this week, had trouble at the 12th, but his double-bogey six there was superbly offset by an eagle at the last.
"Obviously it's a nice way to finish, with an eagle," the four-time major winner said on www.pgatour.com "With the conditions as tricky as they are (on Sunday), hopefully I'll be in with a shout (on Monday).
"I don't feel as under pressure with my long game now to hit it within three feet the whole time. I feel I can give myself chances from 10, 15, 20 feet and have a good chance of holing them.
"It's amazing what one good round does - just that little bit of confidence from (Saturday) carried into (Sunday). I made four nice birdies in a row on the front nine, and some good putts on the back nine as well. It bodes well for the future."
Open champion Henrik Stenson was 10 shots off Casey's lead on five under after a 70, tied with former Masters champion Adam Scott (70) and world number three Jordan Spieth (72).
World number two Dustin Johnson slumped down the leaderboard with a four-over 75 and found himself four under overall after three rounds, among a cluster of players including world number one Jason Day (68) and Scotland's Russell Knox (69).
England's Luke Donald was level par after signing for a third-round 72.