R1 LEADERBOARD US unless stated -7 Ben Curtis, Jim Furyk, Todd Fischer -5 Harrison Frazar, Robert Allenby (Aus), Chad Campbell, Chris Couch -4 Stuart Appleby (Aus), Scott Gutschewski, Craig Perks (NZ) Selected others: -1 Luke Donald (Eng) +1 Vijay Singh (Fij) +2 Tiger Woods

The trio fired seven-under rounds of 64 at Cog Hill in Illinois on Thursday to leave Tiger Woods and Vijay Singh trailing in their wake.

Woods carded 73 as Singh shot 72, while England's Luke Donald took 70.

"I didn't really play all that well today," Woods said. "Didn't putt well, didn't play well, just had tough day."

Furyk opened with a birdie and picked up four straight shots from the fifth before a final birdie at 15.

This game is going to beat you up if you dwell on things too long Jim Furyk

The 2003 US Open winner was pipped to the Barclays Classic title by Ireland's Padraig Harrington last week, after squandering the lead in the final five holes.

"Obviously I was disappointed," said Furyk, winless since 2003 but with three runner-up finishes this season.

"I played well all week but made a few key mistakes down the stretch that left the door open.

"It's something I have to live with and it's something that I have gotten over.

"This game is going to beat you up if you dwell on things too long. I kind of looked at the situation, I looked at what I could have done better.

"But I've never felt I was in a position in this game where I felt like I'm owed a win.

"Of course, I would have loved to have won a golf tournament this year instead of having three seconds."

I didn't really get much going Tiger Woods

Curtis, who has missed the cut in 12 of 14 events, also began well, mixing five birdies with an eagle on the par-five 15th.

"I am in a slump and haven't played well all year," Curtis said.

"I had a couple decent tournaments...it's a long year and I try to stay positive.

"It's just been a struggle with the game. I mean, there's no other way to explain it. I don't want to say it was this and that, because it wasn't. It was all a part of how I was playing."

Sitting two off the leading trio on five-under 66 are Americans Harrison Frazar, Chad Campbell and Chris Couch and the 2000 champion Robert Allenby of Australia.

Woods, who needs just under $57,000 to reach the $50m mark in career earnings, struggled on a hot, humid day at Cog Hill that saw the start of play delayed an hour because of rain and lightning.

Woods birdied the sixth but three bogeys on the back nine against a single birdie left the Masters champion nine off the pace.

"I didn't really get much going," Woods said.