18 July 2010 16:22 GMT

Starting two groups ahead of the leader, Lee Westwood appeared to be sticking religiously to his pre-round game plan, which was to aim to make a steady start to his round. And it was after he had reeled off eight straight pars that Westwood finally decided the time had arrived to step up a gear, with his first birdie of the day at the 9th, to move to eight under par.

Martin Kaymer appeared to singing from Westwood’s hymn sheet for the opening five holes, but he too must have come to realize that 18 pars wasn’t going to be good enough to win the Open, and he has now made a major move to improve his position on the leader board with birdies at the 6th and 9th holes.

The lanky Swede, Henrik Stemson, has also got the message to step on the gas with a birdie at the eighth that moved him to eight under par. The biggest move up the leader board, so far, from a non-European player within striking distance of the lead, has been from American, Sean O’Hair, who has collected two birdies on the front nine.

This still leaves him a considerable distance behind the leader but the fact that Oosthuizen had just dropped a shot to par at the 8th may give the American something to shoot for on his back nine.

Meanwhile, up at the head of the proceedings, Casey’s birdie at the 6th, that gave him back the precious shot he dropped at the second, has helped to settle him down and he is now starting to play well enough to be able to exert more pressure on the leader. The South African’s lead had now been cut to three shots, and both men will be hoping they can pick up a birdie at the short but very dangerous par four ninth hole.

However this gutsy South African golfer has no intention of meekly surrendering his lead without a fight. And he emphatically underlined this fact by driving the 9th green and then draining his 30 foot putt for an eagle two that may yet have a vital impact on the outcome of the Championship. Casey also drove the green but had to be satisfied with a birdie three that keeps him in touch, but only just.

UPDATE: 17:40BST

One of the main problems the chasing player are experiencing is not being able to get close enough to the pins with their approach shots.

The wind has continued to blow fairly strongly throughout the day and it has slowly but surely started to firm up the fairways and more importantly, the putting surfaces. As a result of the heavy rain that fell during the early rounds, the greens became much more receptive, allowing the players the option, when the opportunity presented itself, to attack the flags and still get the ball to stop.

Because the putting surfaces have now become firmer, it has become much more difficult to control the ball when it lands on the greens, especially on downwind holes. And having to putt from the 20 to 30 feet range, and sometimes beyond, is not exactly conducive to making birdies.

One the other hand, from this point on Oosthuizen will be perfectly happy to par in. As things currently stand, with only 4 holes left to play, it will either take a major miracle from one of the chasing players still forlornly hanging on to his coat tails, or a collapse of epic proportions for the South African not to be crowned Open Champion.