By Rob Hodgetts
BBC Sport at St Andrews
Tiger Woods held off a three-pronged attack to take a two-shot lead into the final round of the Open.
Woods carded 71 to edge to 12 under as Jose Maria Olazabal, Retief Goosen and Colin Montgomerie loomed into view.
Olazabal charged to 10 under with a 68 as Montgomerie, playing with Woods in the final group, made a birdie at the last to end on nine under after a 70.
Goosen (66) also climbed to nine under with Spain's Sergio Garcia and American Brad Faxon one stroke further back.
Olazabal's challenge was ignited with an eagle at the 12th to reach 10 under, while fellow Spaniard Garcia eagled the ninth to boost his quest for a first major.
But it was Woods, the nine-time major champion, who was best able to cope with fairways and greens that were firming up and becoming faster in the hot sun and freshening breeze.
"I thought if I shot under par for the day, the way the day was turning, I more than likely would have a piece of the lead," said Woods.
"No-one made a bunch of birdies coming home, so to have the lead all day and end up with the lead is pretty sweet.
"And having the experience to call on and knowing how to handle going out there and playing with the lead, hopefully I can put a quality round together on Sunday."
US Open champion Michael Campbell (68) and world number two Vijay Singh (71) were at seven under, while Northern Ireland's Darren Clarke (67), Scotland's 1985 Open winner Sandy Lyle (69) and 1995 St Andrews victor John Daly were in a logjam on six under.
The day was billed as a last-group shoot-out between world number one Woods and Montgomerie, Europe's inspirational Ryder Cup star, also desperate for a maiden major victory.
Montgomerie and Woods was the dream pairing for St Andrews fans
The roar that greeted home favourite Montgomerie as he strode on to the first tee was deafening, while nine-time major champion Woods, attempting to win a second Open at St Andrews in five years, teed off to polite applause.
Montgomerie, four shots adrift at the start, was cheered all the way down the first on his way to a safe opening par and he earned his first shot back on Woods when the American three-putted the second.
A huge media scrum and a massive throng of vocal supporters dogged their every move, but both held firm to birdie the par-five fifth.
Woods, though, found a gorse bush with a pushed drive on the sixth and the resultant penalty drop cost him another stroke, and a diminishing two-shot lead over the Scot.
A birdie on the seventh for Woods kept Montgomerie at bay but the former champion found more trouble on the driveable par-four ninth and settled for par as Montgomerie's perfect drive set up a birdie.
Thriving on the competition, Montgomerie played his second to five feet on the 10th and sunk his putt to the delirium of the crowd to climb into second on his own at 10 under, just one back.
But a lagged first putt on the short 11th left him too much to do for par and Woods regained his two-shot lead as Olazabal, who only made the tournament when Seve Ballesteros pulled out, also faltered up ahead.
Woods picked up another shot on 12 after virtually driving the green, and both he and Montgomerie missed makeable birdie putts on the long 14th.
The lead was quickly halved on the 16th as Woods fired his approach long and chipped back 15ft past en route to a bogey, while Olazabal birdied the last.
But the Masters champion showed his mettle with a brave par putt on the infamous 17th as Montgomerie slipped up with a Road-bunker induced bogey.
In the cauldron atmosphere of the 18th, restored to gladiator pit after the triumphant scenes of Friday, both Woods and Montgomerie displayed inner steel to make birdies and set up an intriguing final day.
"That's one less shot that I will have to find out there somewhere tomorrow," said Montgomerie after sinking his 12-footer.
Montgomerie will play with Goosen, with Olazabal and Woods in the final group.