Forced to play 36 holes after the first round was washed out by rain on Thursday, Furyk rocketed into contention with a course record eight-under 62 and carried the momentum into the afternoon with tidy 66 to get to 12-under.

Despite his stellar play, Furyk was unable to shake off Villegas, who kept the pressure on with a four-under 66 and was working on a bogey-free third round going three-under through 13 holes when play was finally halted because of darkness.

'I'm a little tired,' Furyk told reporters. 'You know when you play 36 it's the last nine.

'Your concentration can wander off but I stayed focused out there.

'I'll be close, I gave myself a chance to win tomorrow.'

Lurking two shots back of the leaders at 10-under was American Brian Gay, who quietly moved into contention with a second-round 67 and was also working on an error-free third round of four-under with three holes to play.

American Anthony Kim was one shot further adrift with one hole to complete.

It was a wild and gruelling day at the Bellerive Golf Club, the leaderboard changing with almost every shot as players went off first and 10th tees and two rounds were staged simultaneously.

With organisers scrambling to get back on schedule, Saturday's play got off to a false start and was halted shortly after it began and delayed 90 minutes by fog.

Spectacular shot-making
Once action got underway the crowd was treated to spectacular shot-making, including aces from Spain's Sergio Garcia and American Bart Bryant.

But it was Furyk who had the galleries buzzing.

Playing the back nine first, Furyk began the day five shots behind overnight leader Villegas and dropped another stroke with a bogey at the 12th.

It would be the only mistake the US Ryder Cup stalwart would make, Furyk marking his scorecard with an eagle and seven birdies, including five straight to close his round.

Furyk had little time to savour his performance heading right back out for the third round mixing six birdies with a pair of bogeys, including one at the last.

'I just tried to pace myself all day knowing we were going to be out there for 36 holes,' said Furyk. 'We're supposed to be athletes, so walking 36 holes should not be that big a deal.'

Vijay Singh, who has one hand on the FedEx Cup trophy and the US$10 million (S$14 million) bonus that goes to the playoff champion after capturing the first two events of the series, has struggled in St. Louis where he is yet to break par, labouring to a level-par 70 in the morning and one-over 71 in the afternoon.

The hard-working Fijian, however, will not be too concerned with his two biggest threats, Garcia and Canada's Mike Weir, also well down the leaderboard. -- REUTERS