An unexpected collapse by four-times champion Tiger Woods threw the WGC Bridgestone Invitational wide open after yesterday's third round.

One ahead at the start of the day and ideally placed to win his fourth consecutive PGA Tour title, the 30-year-old American dropped four shots in a row on his way to a one-over-par 71.

That left Woods tied for second at eight-under 202, one stroke behind pacesetting American Stewart Cink who fired a joint best-of-the-day 64.

Level with Woods were compatriot and playing partner Davis Love III, after a roller-coaster 70, and Briton Paul Casey (64).

Jim Furyk dropped two shots over the last three holes for a 69 to slip to fifth place at seven under, one better than fellow American Lucas Glover (69).

Hunting his fifth victory at Firestone in his last seven starts, Woods began the day in expected fashion.

After parring the first two holes, he chipped in for birdie from behind the green at the par-four third to forge two ahead of the chasing pack at 10 under.

However, a three-putt to bogey the par-three fifth triggered the world number one's dramatic slide. He pushed his tee shot into the right rough at the sixth before three-putting the seventh and eighth.

Out in three-over 38 and six under for the tournament, he trailed leader Love at that point by four strokes.

Love capped a blemish-free outward nine with birdies at the eighth and ninth. He struck a superb approach to five feet at the par-four 10th to forge three clear of the chasing pack at 11 under before dropping three shots over the last seven holes.

Woods rallied on the back nine to climb back into contention, holing an eight-footer to birdie the 13th and producing his second chip-in of the day at the 17th.

Casey, a virtual certainty for next month's European Ryder Cup team, holed a five-footer at the last for his eighth birdie of the day.

"I'm very happy," the 29-year-old Englishman said. "The goal today was to grab a couple under par if I could and maybe sneak into the top 10.

"It was one of those days that went nicely for me and I capitalised on the opportunities I had."

Padraig Harrington shot 70 to remain on four over midway through the field while Paul McGinley also shot 70 but he is 12 over.