Tiger Woods was looking to press home his advantage over Rory McIlroy in the race for the FedEx Cup £6million jackpot in Atlanta today.
An opening four-under-par 66 at the Tour Championship gave Woods a share of the overnight lead with England's Justin Rose.
World number one McIlroy, winner of three of his last four events, was back in a share of 12th place after losing his head-to-head with Woods by three shots.
"I hit a lot of good shots - I hit a couple of really good putts that lipped out, but other than that it was a really good day," said the American, who came into the week knowing that like points leader McIlroy a tournament win would also give him the huge play-off bonus.
"Most of the summer I've played well. It was nice to get that week off last week and get a little bit of rest - I felt fresh.
"I enjoy playing with Rory. He's a great kid. Over the years there are certain pairings for me that I've enjoyed and Rory is one of them.
"I think that is the whole idea of the play-offs. Trying to get the top players all playing more often, but also in the same group.
"You figure the top players are going to gravitate towards the top of the points list and hence you're going to have these type of pairings throughout the play-offs.
"I've had Rory three of the four events. I think it's worked out the way that our Tour wanted it to.
"You probably don't believe this, but I get along really well with a lot of guys out here. Rory is no different.
"I give it, they dish it and we have a great time.
This is a fraternity out here - that's one of the great things about being out here for 17 years."
McIlroy said: "If you don't hit fairways it's hard. I wish I could have shot a couple of shots better, but I'm in a good position."
As for playing with Woods again he added: "It was good. I always say groupings like that have a great atmosphere, a great buzz."
Rose, despite entering the week ranked 24th, still has a chance of the £6million pay-out - plus another £900,000 for the tournament - under the way the points are reset before the final event.
"Just being here at this tournament is a good feeling," he said.
"I think 21 of the top 22 players in the world are here, so that gets your juices flowing.
"From the FedExCup point of view it's a position of having nothing to lose, really. Obviously I'd like to be much higher up the rankings, but maybe being a little bit looser is going to help me.
"I've only got this tournament on my mind. A lot of the other guys have two trophies on their minds."
He and Woods lead by a shot from Americans Steve Stricker, Matt Kuchar, Bo van Pelt and Scott Piercy.
Sergio Garcia is alongside McIlroy, but Luke Donald and Lee Westwood are 22nd and 26th respectively after rounds of of 71 and 72.
Collated first-round scores (USA unless stated, par 70):
66 Tiger Woods, Justin Rose (Eng)
67 Steve Stricker, Bo Van Pelt, Matt Kuchar, Scott Piercy
68 Hunter Mahan, Zach Johnson, Robert Garrigus, Adam Scott (Aus), Brandt Snedeker
69 Phil Mickelson, Dustin Johnson, Rory McIlroy (NIrl), Jim Furyk, Sergio Garcia (Spa), Bubba Watson, Ryan Moore
70 Keegan Bradley, Jason Dufner, Louis Oosthuizen (Rsa)
71 Luke Donald (Eng), Carl Pettersson (Swe), Rickie Fowler, Webb Simpson
72 Ernie Els (Rsa), John Senden (Aus), Lee Westwood (Eng)
74 John Huh (Kor)
75 Nick Watney
