Westwood dropped shots, due to poor drives, at the 16th and 18th, but a 71 left him at two under and two behind the joint leaders, Miguel Angel Jimenez and America's Chris Perry. Westwood must win to have a chance of winning his first Order of Merit, and then Montgomerie can still hold on by finishing third.
Monty dropped back to one over, but his hopes rest with the impressive list of contenders sharing third place at three under, anyone of whom can win and ensure Montgomerie's No 1 spot for him. The players in question are Tiger Woods, Nick Price, Tom Lehman, Justin Leonard and Hal Sutton.
"It was not an easy day and a 71 was a good score," Westwood said. "I didn't play the last three holes well but they could easily have been three sixes instead of three fives. As I said at the start of the week, it's all going to come down to the last day." He will be hoping it does not come down to the last hole, however. "I still can't figure out what to hit off the 18th tee. I've tried two drivers and a three-wood so far but it seems to be a par-four with no fairway."
Montgomerie returned a 72 for the second day running. "Not right now," he told inquisitors at the recorder's hut. How often has the Scot spoken about needing to hole a good putt early on to set up a good round. On the second green, he had a birdie chance but was distracted by the warning signal of a reversing rubbish truck. When it stopped, and Monty had bent over the putt, it roared off again and he had to back off again.
The putt was missed, as were the next few before he three-putted at the sixth. A further indication of his mood came with an altercation with a spectator at the third green, whom he accused of being in his line.
From tee to green, Montgomerie outplayed Jose Maria Olazabal, but - helped by a couple of long putts, one at the eighth for birdie and another at the tenth for birdie - the Spaniard scored a 69 to move to two under, three ahead of the Scot. Monty finally holed a putt for a birdie at the 15th and then, after chipping over the green, holed from the back fringe at the last for a par.
Ollie is one of the toughest players on himself as well as one of the more diplomatic about others. "Monty was striking the ball really well," he said. "He is struggling to score because he didn't make a single putt until the 15th.
"Sometimes he is a little bit tough on himself, but so are some of us. No one is perfect. Monty is the way he is. He hasn't done bad, has he, with probably seven Order of Merits in a row. I'd like to see him smile a bit more but it is not happening at the moment."
The wind picked up again yesterday and switched to the opposite direction, coming in from over the Andalucian hills. It proved a shock to some of those Americans playing the course for the first time, but then Mark James, three under overnight, slipped to a 74. Phil Mickelson put two balls into the water at the par-five fourth for a nine, while Jeff Maggert, who finished seven-five-eight, six-putted the last green, missing from two feet for a par.
Jimenez is in prime form, his confidence as high as it has even been, and knows Valderrama in all conditions. He went to the turn in 32 and parred the back nine until a bogey at the last. Jimenez is inspired in front of the Spanish gallery, winning earlier in the year in his home town of Malaga and last week in Jerez at the Volvo Masters.
It would be an impressive double in a fortnight for Jimenez to complete today, but then Woods won the US Tour Championship last week and he will be hoping that he can make it four wins from his last four starts, and five in six. His challenge seemed to have stalled before, for the third day running, he produced an impressive finish. The world No 1 holed from 25 feet up the tier on the 17th for a birdie and added another from 18 feet at the last.
"It would be pretty neat to win both last week and this," Woods, after a 70, said. "They are both elite fields with guys who have played well to get into them. I'd take a lot of pride in getting into the winner's circle tomorrow."
Montgomerie would be the first to offer his congratulations.