PGA CHAMPIONSHIP: THE TEMPTATION is always to look too far ahead, but Paul McGinley - in his 17th season on tour - is too hardened by life's experiences to know not to tempt fate.

Yesterday, for instance, it seemed as if every corner turned on the West Course held the potential for ambush, only for him to outmanoeuvre them all and reach the midpoint of the BMW PGA Championship with a record 36-hole total and a four-stroke advantage on those cast as pursuers.

No matter what those chasing him threw his way, be it the course-equalling 65 of Miles Tunnicliff or the elegantly manufactured 69 of Robert Karlsson that concluded with a hat-trick of birdies, the 41-year-old Dubliner - without a win on tour since the 2005 Volvo Masters - managed to keep a straight course in his bid to claim the European Tour's flagship title.

In shooting a 66 to follow Thursday's opening salvo of 65, McGinley's halfway total of 131, 13-under-par, proved to be a shot better than the previous record low set by Ernie Els in 1994 and later matched by Colin Montgomerie (2000) and Andrew Oldcorn (2001). More importantly, it gave him a four-shot lead over Tunnicliff and Karlsson, with the trio of Oliver Wilson, Soren Kjeldsen and Marcus Fraser a shot further back in tied-fourth.

McGinley has hardly put a foot wrong so far, his only bogey in the 36 holes coming on the first yesterday where he missed the fairway with a three-wood and, ultimately, failed to hole a six-footer for par.

Otherwise, it was a patiently and well-constructed round that finished in some style with a run from the 16th that went birdie-par-birdie-eagle to cover the back nine in a mere 31 strokes.

As Graeme McDowell, in his group for the first two rounds, remarked: "If Paul keeps doing that, he's going to be unbeatable . . . he's played a lot of mistake-free golf, and he is going to be a hard man to catch."

Throughout his career, McGinley has always been comfortable with the driver in hand, and, as you'd expect, he has been finding a lot of fairways and hitting a lot of greens-in-regulation. The difference this time, it seems, is that he has been holing his fair share of putts, with the result that grins rather than grimaces are accompanying his efforts.

"It's not like all of a sudden the hole is the size of a bucket. It's just that I'm rolling the ball towards the hole . . . and it is going in. Everybody knows these greens are difficult and the ball does snake a bit on them. I'm not overconfident with the putter, but I do feel in control of what I'm doing. I'm rolling the ball at the hole, and it is going in. So, there's no real X-secret. The fundamentals I'm working on are the same fundamentals I've been working on the last seven months with Paul Hurrion."

McGinley turned to Hurrion over the winter after seeing how he had influenced the putting of Pádraig Harrington, Bradley Dredge and Phillip Archer. Hurrion, a devotee of the biomechanics way of teaching, provided the specifications - based on McGinley - for TaylorMade to make a new putter for the Dubliner.

As McGinley put it, "there's no way I could change my golf swing as much as I've changed my putting . . . it is actually quite different from what I used to putt like before in terms of technique."

So, now, after months of waiting and waiting for it all to click into place, it has done, and on greens that would frustrate the patience of a saint.

Indeed, such frustration manifested itself yesterday, particularly in relation to Paul Casey's reaction to discovering that the ninth green had been flooded overnight by a burst sprinkler head but that players hadn't been informed. After intentionally playing an approach to the ninth some 10 yards short of the flag expecting it to release forward on the firm greens, Casey was amazed to find the ball spinning back eight yards instead.

"Someone laughed at me and said, 'you clearly didn't hear the sprinkler head popped this morning and flooded the green'," recalled Casey, who muttered a few choice words under his breath and later had an impromptu on-course discussion with chief referee John Paramour.

Casey, who argued that players should have been informed of the incident and claimed his words were "muttered under my breath and not directly aimed at anyone in particular", shot a 69 to finish on 139 to be still well in the hunt going into the final two rounds.

Some other big names, however, failed to survive the cut. Justin Rose, Ernie Els, Niclas Fasth, Jose-Maria Olazabal, Darren Clarke and Rory McIlroy were among those who failed to come to terms with the demands of Wentworth, with the cut falling on one-over-par 145, while Lee Westwood was forced to withdraw after five holes of his second round because of food poisoning.

For McGinley, who has slipped to 157th in the world rankings, this weekend is vital as he goes in search of the biggest win of his career. He faces a true challenge over the next two days. Not only would a win provide him with the biggest individual success of his career - with a top prize of €750,000 - it would also put an end to the nuisances of having to attempt to qualify for the remaining majors this season.

Yet, McGinley only had to look at the last group out on the course last evening to be warned of the potential for his pursuers to charge over the weekend when Englishman Robert Dinwiddie finished with a run of five successive birdies for a course record of 63. But then, they say forewarned is forearmed.