Aussie Jason Day and American Jim Furyk are tied for the lead after day three of The Barclays in New Jersey - the opening event of the four-tournament FedEx Cup finale.
Day carded a three-under 68 and Furyk a 69 to post nine-under but a bunched leaderboard means the tournament remains wide open going into the final day.
Hunter Mahan (68) is a shot back while there are seven players a further stroke in arrears on seven-under.
Day's colourful scorecard included seven birdies (at 2, 3, 6, 10, 15, 16 and 18) but also two bogeys and a double bogey seven at the par five 13th.
By contrast, the steady Furyk returned a bogey-free card which featured birdies at 13 and 16 and a superb par save at 18.
Day, who won the WGC-Accenture Match Play earlier this season, said: "Obviously to have a double bogey and a bogey on the par fives, which are the holes that you want to try and capitalise on, is very disappointing, a little frustrating. But to birdie 16 and 18 was a good confidence booster going into tomorrow's round."
Rory McIlroy's hopes of securing a fourth straight victory after winning two majors and a WGC event in his last three starts didn't get the boost he had in mind following a one-under 70.
The four-time major winner started well with birdies at the first and fifth but gave the shots back with bogeys at nine and 11. A birdie at 16 was his only other gain of the day and he'll start the final round five shots off the pace.
He tweeted later: "Just couldn't get it going on the greens at all today... New day tomorrow and not as far back as I thought I'd be at the end of the day!"
Threatened
Justin Rose also threatened to surge into the thick of contention after almost holing his tee-shot for albatross on the par four fifth hole.
The Englishman tapped that in for eagle from a foot and also birdied the sixth to get to seven-under. However, he hit a rocky patch with bogeys on 7, 9 and 12 before a birdie at 14 and four closing pars saw him card a second straight 70 and finish at five-under.
Rose said later: "I guess I'm not the only one making mistakes out there. If I get it going low and post a number, anything's possible."
Gonzalo Fernandez-Castano is now the leading European on six-under after the Spaniard fired a three-under 68. He will go into the final day in tied 11th, just three shots back.
Adam Scott, the joint overnight leader after a 65 on Friday, shot 10 shots worse on Saturday and fell all the way down to four-under - now five off the pace.
Henrik Stenson, the current FedEx Cup champion, saw his hopes of victory go up in smoke as he recorded a nine on the par four fourth hole and returned a 77.