When a race is half-run, only the foolish or the naive lose the run of themselves. Of all places on this earth, Augusta National - despite its outward appearances of serenity - is a course where any indication of over-confidence is rewarded with sinister rebuke, an admonishment that can cause demons to inhabit a golfer's mind. It's a recipe for failure.

Yesterday, as a stiff breeze blew across this stretched-out course to accentuate the challenge, those with aspirations of grandeur in the US Masters kept their self-control, including Chad Campbell, an American without a major title, who assumed the midway lead after posting a second round 67 for 138, six-under-par.

"I like where I'm at," remarked Campbell, runner-up in the US PGA in 2003.

But he had only to look at the quality names in pursuit to know that the hard part of the task has still to come. Crowded behind Campbell was an ominous list of those who know what it takes to win majors, among them Phil Mickelson, Ernie Els and Vijay Singh; and those who believe they can.

In the list of those looking to make a breakthrough were two Irishmen, Darren Clarke and Padraig Harrington, who patiently plotted a route around the treacherous course to become contenders, moving into the top-10 at the half-way stage.

Clarke shot a round of 70, to lie on two-under-par 142. Harrington also signed for a 70, putting him a stroke further back.

Expectations? They've been around too long to let their minds race ahead. Clarke, adopting a new, relaxed approach brought about in part by the treatment his wife, Heather, is having for cancer, admitted: "I'm just taking whatever the course gives me. C'est la vie."

For Harrington, his emergence as a contender marked a remarkable turnaround. In his first round on Thursday, the Dubliner was five-over-par after seven holes.

Rather than capitulate, he showed his mental strength and ground out a 73. Yesterday his first action upon emerging from the recorder's cabin was to high-five his sports psychologist, Bob Rotella, who appreciated more than most the recovery that Harrington had orchestrated.

Of the mental fortitude he demonstrated and the bond with Rotella, Harrington remarked: "That's what we work on together, being able to overcome adversity and deal with things when they aren't going well. I stayed positive (on Thursday) and came back strong and stuck to my guns today."

Harrington's round in the tricky crosswinds was impressive. He hit 12 of 14 fairways, an indication that the 47in driver he has put into this bag for the Masters has worked splendidly. His power was evident on the last, where he hit a drive of 315 yards which left him with only a wedge to the green. He rolled in an eight-footer for the fourth birdie of the round.

"I am swinging the club better than I have all year. I have improved my swing, and I am comfortable with it - it was just a matter of bringing it on to the golf course. It was just a matter of being patient this week.

"You never get in a comfort zone out there. After seven holes (on Thursday) I was five over par and I don't know what it changed mentally in me, but it has got me to the stage where every time I get up there I am trying to get it close, I'm trying to make birdie.

"I am taking on the shots a lot more positively and I am not worried about the outcome of the shots. I'm playing a lot more relaxed, carefree golf. For the first seven holes (on Thursday), I was probably a bit cautious, a bit defensive in my swing. Now I'm more positive about what I am doing."

Although the wind added to the course's difficulty, some tees were moved forward. On the fourth, for example, players were hitting from the old tee - 40 yards in front of the new one - because of the right-hand pin location.

It still proved to be troublesome nonetheless, especially for first-round leader Vijay Singh, who took a double-bogey five there after putting his tee-shot into the rhododendron bushes over the back of the green. He promptly double-bogeyed the fifth hole too, and took his third double-bogey of the round on the 13th as the Fijian slipped down the leaderboard.

Mickelson, too, had his problems, including putting his approach to the 11th into Rae's Creek. But the 2004 Masters champion, who signed for a 72 for 142, said of his position: "I'm in a good position heading into the weekend. I'm excited."

If Augusta is perceived as being a tough course from which to fend off pursuers, Campbell didn't seem too perturbed by the role handed to him.

"My goal is to compete in all the majors, and I haven't done that as well as I'd like obviously. But I've got off to a good start to the season," said Campbell, who won the Bob Hope Classic in January.

This is a step up from that; but Campbell has shown in the past a tenacity of champions.

So too have others, however. He'll be looking over his shoulder.