Graeme McDowell and Padraig Harrington know they have a long slog ahead in a US Open marathon at Bethpage Black.

Upbeat McDowell is trying to work out how to last the major pace for 72 holes after a sensational 69 gave him the early clubhouse lead on one-under par.

But a super-serious Harrington was furious with himself after a ragged, six over 76 left him down with the stragglers and in danger of missing his fourth cut in a row.

The Dubliner was frustrated by poor putting but still believes that it is not too late to make up lost ground in a weather-hit championship that looks likely to run into Monday.

Just two shots adrift of Tiger Woods, who posted a four over par 74, Harrington knows that he must recover his usual, razor-sharp short game if he is not to end up packing his suitcases for home when he eventually completes his second round today.

“Level par wins US Opens and it is still possible,” he said after taking 34 frustrating putts. “I just need to putt a lot better. I am struggling on the greens and every time I make a mistake I am not able to recover and that is really killing me.

“I am getting no momentum and I have got to do better on the greens the next couple of days. You are going to make some mistakes and you have got to recover from those.

“I struggled early on and any time I made a mistake I got the worst out of the hole. When you are not holing those putts for pars it puts you under more pressure off the tee.”

With no rain to worry about yesterday, Harrington faced a 25 foot par putt on the seventh when he resumed at 7.30 am but missed it to slip to five over par.
And he paid the price for a wayward tee shot at the ninth, where he could only move the ball a few feet in the rough and ended up having to hole a 12 footer for a bogey.

Digging deep, his frustration grew when he hit a six iron to three feet at the 11th but failed to convert the birdie chance and then slumped to seven over par as another bad drive led to a bogey at the 12th.

He bounced back bravely with birdies at the par-five 13th and short 14th but then racked up a double bogey six at the 15th, where he was left waiting an age to hit his approach after his best drive of the day.

Bunkered greenside, he compounded the error by three putting and confessed that he cannot afford to carry on this way if he is to have any chance of contending.

He said: “I don't mind missing a green because on another day I would get up and down - I excel at that sort of thing. But every time I make a mistake I am compounding it by making the worst score on the hole that I can and I have got to make sure I tidy up my short game.”

The players who sat out Thursday’s rain delay appear to have had the luck of the draw, though heavy rain is expected when they complete their second rounds this morning.

Yet Harrington knows that anything can still happen and insists that he is looking at the leaders rather than the cut line

He said: “I won the Open from the wrong side of the draw last year and there are still 54 holes to go. I am not thinking about the cut. I am thinking about the top of the leaderboard. I swear I am.”

While the Dubliner has shown that he can come from behind to win - as he did in last year's US PGA or the Open at Carnoustie in 2007 - McDowell has yet to prove that he can withstand 72 holes of mental torture to win a major.

In 2006 he led the Open at Hoylake after a first round 66 but faded to 61st in the end.

It was a similar story at Birkdale last year, where was the joint first round leader but carded an 80 on Saturday and did well to make the top 20.

This season he has paced himself nicely by playing a limited schedule and he hopes he will have the energy and the mental strength to keep up the pace for four rounds this time

After posting the best score of his short US Open career, McDowell said: “I have led a few majors after day one. I am trying to stick around for the weekend and trying to position myself as well as I can to compete on Sunday afternoon.

“There is no point in being top of the leaderboard right now. Posting a nice number in the first round is not going to hurt. But I can’t get ahead of myself mentally and stay in the present.

“I have to keep doing what I have been doing over the weekend and realise it is going to be a tough slog.”

The Portrush ace resumed his first round at the 17th (his eighth) on one-over but birdied the hole and then picked up further shots at the second and fourth to lead outright on two under.

He bogeyed the par-four sixth after a bunkered approach but saved a great par at the seventh and parred his way home to share the clubhouse lead with US amateur Drew Weaver on one under 69.

Knowing he was likely to be trailing by some distance as the afternoon starters got the best of the weather, he said: “I’d love to get back out there again but I have to get some rest for tomorrow.”