Tiger Woods is cruising towards his sixth Bridgestone Invitational title after going five shots clear midway through the final round.

The world number one, a stroke behind South Africa's Rory Sabbatini at the start of a damp day at Firestone Country Club, birdied four of the first six holes before reaching the turn in four-under 31.

Woods was fortunate to save par at the ninth, where he chipped in from just off the green, to stay at seven under overall with Argentina's Andres Romero alone in second place, also after nine holes.

Sabbatini, playing with Woods in the final threesome, double-bogeyed the ninth to slip back into a tie for third at one under with Britain's Justin Rose, who had completed 11 holes.

The South African, bidding for his fifth PGA Tour title, had birdied the opening hole before losing ground with bogeys at the fourth and fifth.

Woods, hunting a third successive victory at Firestone and his 14th individual title in a World Golf Championships event, made the best possible start.

The 31-year-old American struck his approach to six feet to birdie the par-four first and picked up another shot at the par-five second after reaching just short of the green in two.

Having struggled with his putter earlier in the week, Woods took advantage of rain-softened conditions by rolling in birdie putts from 16 feet at the fourth and sixth to tighten his grip.

After his second shot at the par-four ninth ended up in the lap of a spectator sitting beside the green, Woods overshot the putting surface with his third before conjuring a magical chip from 17 feet to salvage his par.

The game's leading player has never finished worse than tied for fourth at this event and was closing in on his 58th PGA Tour title as the perfect warm-up for next week's PGA Championship in Tulsa, Oklahoma.

Reuters