RUGBY/Six Nations: " Look...if you had...one shot...or one opportunity...To seize everything you ever wanted...one moment...Would you capture it...or just let it slip?" Eminem's words are perhaps more fitting for Ireland, writes Gerry Thornley, Rugby Correspondent.

A shot at a Grand Slam scarcely even comes along once in a lifetime, for them. Hence, this momentous clash is much more of an entity in itself. For England, however, the present is heavily tinged with both the past and the future.

Three last-day Grand Slam failures in a variety of European capitals have, naturally, left a mark on their collective psyche. In theory, it should ready them for the occasion that lies ahead. After beating Scotland last Sunday, one of today's 50-cap men, Matt Dawson, spoke of how uptight he'd been on previous grand finales. Play the game, not the occasion, will presumably be a mantra in both camps. Easier said than done, of course.

"That's the aspiration, to not get wrapped up in the emotion of the occasion," admits Eddie O'Sullivan, "but if you didn't you'd want to see a neurosurgeon because it's just the way the game is. There will be a sense of occasion, there will be a lot of tension and there will be a lot of pressure on people. But that's where guys want to be."

At least the Irish players know that barring injury, all 22 of them should be going to the World Cup. However, for several English players, possibly facing their last tilt at a Grand Slam, the October global fest in Oz might also be on the line here.

Going strictly on form so far though, you can without doubt more easily see England winning, simply because you can see them scoring points more easily. With more target runners up front, Steve Thompson, Lawrence Dallaglio, Richard Hill, etc, the sniping of Matt Dawson, Will Greenwood's craft, and a more balanced attacking outside unit, they have more potency.

England have applied far more continuity, hitting heights (especially in the first half-hour against Italy) Ireland haven't even aspired to.

And then there's Jonny Wilkinson. The record-shredder spent two-and-a-half hours practising his kicking game with Paul Grayson and Dave Alred in Anglesea Road yesterday. He just doesn't miss. Every touchdown is pretty much a guaranteed seven-pointer.

For whatever reason, the six-day turnover in Italy, the conditions against France, nerves against Wales, Ireland have kicked more ball than anyone else, whether via David Humphreys, Brian O'Driscoll, Geordan Murphy or even Denis Hickie.

They'll be particularly mindful of territory with Wilkinson around, but even so there'll surely have to be a greater emphasis on ball retention, with Victor Costello and Kevin Maggs used in midfield as target runners to free up space for the strike runners out wide off second phase.

There lurks the suspicion/hope (dilute to taste) that Ireland haven't shown their full hand yet. But unless they have an ace, or preferably four, up their sleeves, then where are they going to win the game?

A herculean defensive effort, Humphreys to kick his goals, and maybe pilfer a try or two off pressure-cum-mistakes. It's not at all impossible, and in another tight end-game, this teamhave forgotten how to lose.

Then there's home advantage. It's unquantifiable, and O'Sullivan has done his damnedest to invoke the Lansdowne roar.

"I want the crowd to relax and enjoy the occasion, but get behind the team at every possible opportunity. The Lansdowne Road factor is huge in this. It's our back yard, and we really need them behind us, because it does improve the performances, and on such occasions great things can happen."

The relatively inexperienced Josh Lewsey will never have faced anything like this. If the home crowd will implore one thing to happen it will be that he drops his first up-and-under.

Early lines in the sand will set the tone, much like Malcolm O'Kelly following up a Humphreys restart after four minutes 18 months ago and thundering into Balshaw on the English ten-metre line.

Jonathan Kaplan will have a major bearing on proceedings, of course. Messrs Johnson, Back and co (or should that be messers?) played Alan Lewis like a violin last week at Twickenham to the chorus of "hands away white." And there are no more vocal auxiliary referees than Johnson and Matt Dawson. With Brian O'Driscoll out at second centre, vice-captain Anthony Foley has been Ireland's conduit with the man in the middle, and he'll need to be big-time here.

Kaplan's interpretation of the scrum may have the biggest bearing - witness the events of Cardiff when Steve Lander did not insist the front rows scrummaged straight. With Phil Vickery and Julian White sidelined, Justin Leonard moved to tight head and the converted flanker Steve Thompson not a renowned scrummager, this may not be such a problem area for Ireland - whose scrum had been strong until a week ago.

Nor should the line-out be a problem. With the switch in this campaign to first winning the line-out, and then using the ball accordingly, statistically Ireland have had the highest return from their throws in the championship.

It's perhaps just as well we didn't have two weeks' build-up to this one. One week is bad enough.

You only get one shot, do not miss your chance. This opportunity comes once in a lifetime...

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Overall record: Played 115, England 68 wins, Ireland 39 wins, 8 draws.

Highest scores: England 50-18 in 2000, Ireland 26-21 in 1974.

Biggest wins: England 46-6 in 1997, Ireland 22-0 in 1947.

Formguide: Ireland - 36-6 v Scotland (away), 37-13 v Italy (away), 15-12 v France (home), 25-24 v Wales (away). England - 25-17 v France (home), 26-9 v Wales (away), 40-5 v Italy (home), 40-9 v Scotland (home).

Leading try scorers: Ireland - David Humphreys, Geordan Murphy, Keith Gleeson 2 each. England - Jason Robinson 3, Josh Lewsey 2.

Leading points scorers: Ireland - David Humphreys 67. England - Jonny Wilkinson 64.

Odds (courtesy of Paddy Powers): To win championship - 7/4 Ireland, 2/5 England. Match betting - 7/4 Ireland, 18/1 Draw, 4/9 England. Handicap odds (= Ireland +7pts) 10/11 Ireland, 16/1 Draw, 10/11 England.

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Replacements: Ireland - G Dempsey (Leinster), R O'Gara (Munster), G Easterby (Llanelli), J Fitzpatrick (Ulster), F Sheahan (Munster), P O'Connell (Munster), A Quinlan (Munster).

England - D Luger (Harlequins), P Grayson (Northampton), K Bracken (Saracens), T Woodman (Gloucester), D West (Leicester), D Grewcock (Bath), J Worsley (Wasps).

Referee: Jonathan Kaplan (South Africa).