All-Ireland SFCqualifier Dublin v Armagh: Like many a tortured drinker in the last-chance saloon, Dublin and Armagh will be looking back wistfully to better days.

Only 10 months ago both teams were on top of their game and fighting out a memorably close encounter for a place in the All-Ireland football final. Now neither are going with any great conviction and the end is nigh for one of them.

Oblivious to such undercurrents, the crowds will be out in force and Croke Park expects a capacity attendance. But word in Armagh is the Saturday throw-in will affect their usually substantial following.

This may not be a story entirely without redemption, as whoever wins is bound to receive a lift to spirits and acquire a bit of momentum going into the final qualifier round - just as Galway did at this same stage two years ago, also against Armagh.

But for this afternoon it's a question of who can halt the tailspin long enough for the other to crash. Armagh's experience isn't unique. Defending the football All-Ireland has become nearly impossible.

The champions emerged last year not only from an exhausting campaign - six of their eight matches decided by just one score, including two replays - but from four gruelling seasons.

Little wonder this year has proved so difficult even without the complicating factor of injury. Going into the fateful first round against Monaghan, manager Joe Kernan was anxious about the number of players indisposed. Former Derry manager Eamon Coleman had told him the one thing you can't plan for when defending an All-Ireland is injury. This afternoon that shadow again falls on the team.

Kieran McGeeney's hamstring injury continues to trouble him despite almost daily physiotherapy and Oisín McConville's participation is similarly threatened. Losing either of those would be a huge setback.

Already considerations of form have ruled out Justin McNulty, John Toal and Ronan Clarke. The last named was a crucial influence on last year's match giving Paddy Christie the worst afternoon of his All Star season and bagging three points in the process. So the team has changed quite a bit since last September. This is often a good thing for defending champions in that it freshens up the team but in this case it's not so much that the newcomers are better but the players they replaced are out-of-form.

Dublin's decline has been marked by a loss of confidence. Of the regulars only Paddy Christie and Stephen Cluxton are playing up to the levels of last year and Senan Connell (when picked) is doing better. But neither Ray Cosgrove nor Alan Brogan have been making the same impact and their goal-scoring threat has receded.

Last week in Clones there was some improvement.

Dessie Farrell's return to the attack gave it a sense of order and stability and with his Na Fianna colleagues, Jason Sherlock and Connell, he greatly improved the goal-scoring potential. The new dispensation of naming the team on the day means the starting 15 are still unknown but vibes from the camp suggest Sherlock will start on the bench.

The win over Derry wasn't without cost and the damage to Darren Homan's shoulder ligaments looks certain to at least inhibit Dublin's best centrefielder the last day. Ironically it was an injury to Darren Magee, who had so successfully replaced an out-of-form Homan, in last year' semi-final that helped turn the match Armagh's way. Now it's Magee who's struggling but he may well play and, given this a sector where the champions are in trouble, Dublin can win ball.

But they will need to improve on last week. Armagh aren't likely to be as harmless in front of goal as Derry proved. Shane Ryan, after last week's excellent display at wing back, may find space harder to come by in the face of Armagh's pressing game. His marking - never his calling card as a defender - will also be under more pressure. And Paul Griffin will have his hands full with Steven McDonnell.

The pay-off for Tommy Lyons's team is that defensively Armagh aren't what they were. McGeeney really needs to be 100 per cent fit to be effective and there is a vulnerability in the corners, which Sherlock on current form - and Cosgrove and Brogan anywhere nearer their best - can certainly exploit.

So much will depend on the day. It's a cliché but particularly true of today. The first team to establish a rhythm will have a big advantage, as it's bound to impact on the opposition's morale. Important factors include how well Dublin start with the frees, which team demonstrates accuracy early on, which big names spark and so on.

One difference between the teams is that whereas Dublin are inching their way towards an improved starting line-out, Armagh appear to be regressing because of lost form and injuries. The champions will be fiercely determined but that may no longer be enough.