US Open 2013: Rory McIlroy is determined not to let the heavy rain kill his buzz at Merion

Rory McIlroy was thinking of running up the Rocky steps at the Philadelphia Museum of Art in the hope of tapping into the warrior spirit of Philly's celebrated celluloid slugger. An afternoon lugging dead pigs in and out of freezers might not be enough to prepare for the right hand that nature is about to throw at Merion today. More than three inches of rain is expected to slam into Philadelphia's leafy north west at just about the time McIlroy is due to tee off at the US Open. Not even the boy Balboa would take on a weather forecast like that.

How contrasting was the scene when McIlroy set out at the 11th shortly after 7am to walk in the footsteps of Ben Hogan alongside Tiger Woods. McIlroy and Woods are grouped today with Masters champion Adam Scott in the tournament's showbiz three-ball. Eight holes was sufficient to loosen limbs and download sight lines on a course new to most.

There was a big smile and a hug from Woods on the 18th tee for the other family member creating a stir this week, nascent TV pundit Cheyenne, his golfing niece. Ignore the insouciance. He could not have appeared more ready.

The drive that followed split the fairway, affirming a sense of destiny unfolding. Woods is so far ahead in the betting there is no great value in taking a punt. The test the hosts had planned has been neutered by the weather. Tropical storms have effectively knocked the teeth out of Merion. The fairways are the colour of goalkeeping jerseys, catching everything thrown at them and the greens are more receptive than a banker's wallet. The heat forecast for the weekend will come too late to rearm this velvet masterpiece with the appropriate defences. Even when he was carding his outward 44 in the third round at the Memorial Tournament, Woods still hit seven fairways.

You wouldn't want to be off line anywhere here. The rough, emboldened by a diet of nitrogen supplements, will win any arm-wrestling contest, but Merion's best defence, her hard running greens, are not coming back this week. Woods's lowly finishes at Memorial and the Honda Classic are collector's items in a season that has yielded four wins and a fourth place at the Masters. Woods is back. All that is missing is the major dressing.

McIlroy was full of beans, too. He has shown episodic flashes of the genius that has brought him major victories in each of the last two seasons. Confidence is the key to McIlroy's week. He has yet to demonstrate the dogged consistency of Woods, but when the putts start to drop he has a turbo dimension every bit as devastating. McIlroy, too, laboured in the windswept acres of Muirfield Village, but arrived here in ebullient mood and buoyed by the company he is keeping.

"As soon as I heard the pairing I was excited by it. There's a lot of buzz and a lot of atmosphere around it and it gets you focused from the first shot, which is sort of what I need. The two majors I've won I've sort of come in a little bit with low expectations. I feel like coming into the US Open my game's in much better shape.

"Last year I came in off three missed cuts in a row and wasn't playing very well. It's nice to come in maybe not under the radar but able to do your own thing, get on with your business and prepare the way you want to for this tournament. I feel like it's close. I've been seeing a lot of positive signs in my game the last few weeks. You always want to go out and play well and you want to contend and win tournaments. I haven't done enough of that this year."

Scott described himself as the third wheel in this line-up. Nice try Adam, but that won't wash. The US Open is only Scott's second appearance since his victory at the Masters two months ago. His pared down schedule is at the heart of his second coming as a serious golfer. Like many a promising youth, Scott struggled to find a route off the plateau that claimed him after the first rush of success. The key, he claims, is the daily five-hour shifts he puts in at home in Albany when he is not contesting events. "Sometimes it's frustrating watching on TV feeling that you are playing well and ready to contend but you just have to have faith in what you are doing. At the start of 2011, when I wasn't playing well, I took six weeks off and looked at every aspect of my game. I came back with a new attitude and a new way of working. Welcome to the semi-retirement club. It works for me."

Despite the quantitative easing afforded by the softer conditions, precision is still required to trigger the flow of birdies. Notionally at least, Merion is made for the shorter hitters, like Luke Donald and Graeme McDowell. There are only two par-5s on the card and they are done inside four holes. Both missed the cut in their last engagement at Wentworth, but McDowell has won twice this year and has a US Open trophy in the cabinet. Donald's wedge will have to be at its sharpest if he is to arrest his recent decline and deliver at a tournament said to be made for him.

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Phil Mickelson 33-1

A bridesmaid five times, Mickelson was sufficiently confident about his preparation here to fly home to California to attend his daughter's graduation. Second last week in Memphis, he is a popular alternative to Tiger Woods at the top of the betting.

Dustin Johnson 40-1

In these conditions this might not be a fair fight. A 62 is out there they say. If so it is in Johnson's gift to deliver it. Long and straight, he need only avoid the rough to ransack this pretty layout in the Philadelphia suburbs.

Scott Stallings 90-1

Don't laugh. Stallings is the form jockey on the PGA Tour, recording a sequence of finishes in his last three outings that are pointing only one way; 4, 4, 2. With a formation like that, don't be surprised were he to score the winner on Sunday.

US Open: First day details

Selected tee-off times (US unless stated, all times BST):

Starting at first hole

12.07pm N Watney, H Mahan, P Hanson (Swe)

12.18pm L Glover, P Casey (Eng), B Haas

5.30pm D Toms, D Clarke (NI), J-M Olazabal (Sp)

5.52pm L Donald (Eng), L Westwood (Eng), M Kaymer (Ger)

6.03pm J Furyk, G McDowell (NI), Z Johnson

6.14pm R McIlroy (NI), T Woods, A Scott (Aus)

Starting at 11th hole

12pm D Johnson, B Watson, N Colsaerts (Bel)

12.11pm S Stricker, P Mickelson, K Bradley

12.22pm M Kuchar, J Rose (Eng), B Snedeker

12.44pm S Cink, S Garcia (Sp), P Harrington (Ire)

12.55pm I Poulter (Eng), J Dufner, B Weekley

1.06pm R Fowler, M Manassero (It), J Day (Aus)

Television

Sky Sports 2, 2pm-12am

Weather

Conditions unsettled, with showers and thunderstorms possible. Maximum temperature: 23C.

Leading odds

5-1 Tiger Woods

10-1 Rory McIlroy

16-1 Lee Westwood

20-1 Luke Donald, Adam Scott

25-1 Graeme McDowell, Justin Rose

33-1 Padraig Harrington, Sergio Garcia, Phil Mickelson, Brandt Snedeker

40-1 Ernie Els, Martin Kaymer, Rickie Fowler, Ian Poulter, Louis Oosthuizen, Charl Schwartzel, Jason Day, Dustin Johnson, Thorbjorn Olesen