Sergio Garcia is two shots ahead of America's Nick Watney after the third round of the Barclays Tournament in Farmingdale, New York.
The Spaniard shot a two-under-par 69 to move ahead of Watney, who carded 71 after sharing the lead with Garcia overnight.
Kevin Stadler is in third place after the day's best round of 65, but Tiger Woods is six shots off the lead.
Lee Westwood is the leading Briton, alongside Woods on four under.
Garcia, seeking back-to-back wins, ensured his place in next month's Ryder Cup when he won the Wyndham Championship last week.
Garcia said: "At the moment, I want to go back to the hotel, take a nice shower, and relax.
"There will be plenty of thinking tomorrow. So I just want to go out there and try to play the way I've been playing, try to believe in what I'm doing as much as I've been doing, and if I manage to win, that will be great.
"If I don't, it will still be great. I'll be giving it my best effort, so we'll see."
Ian Poulter and Padraig Harrington slipped out of contention after carding rounds of 75 and 76 respectively.
LEADERBOARD (US UNLESS STATED)
- -10: Garcia (Spa)
- -8: Watney
- -7: Stadler
- -6: Snedeker, Estes
- -5:Harman, Chalmers (Aus), Moore, Senden (Aus)
- Selected others: -4:Westwood (Eng), Woods, Mickelson
