Mayo v Tyrone: Even by the standards of the genre, last March's league meeting between the teams looks an unreliable indicator to this afternoon's Bank of Ireland All-Ireland football quarter-final.

Just a fortnight after the death of Cormac McAnallen, Tyrone honoured the occasion in Castlebar by doing what they know best and in the awkward circumstances Mayo had no answer.

But before drawing even that thin thread of precedent from the encounter it's worth pointing out that Mayo field only five of that team whereas Tyrone have a more representative 10.

Bringing the teams' situations up to date, Mayo have had the better of the championship to date. Their emphatic wins over Galway and Roscommon nailed down a first Connacht title in five years while Tyrone lost their way defending the Ulster title and have had to take the circuitous route since.

The problem for Mayo is the increasing sense the champions have been purged by defeat and are now rapidly picking up momentum.

The qualifier matches have been against useful opposition, with the exception of a dispirited Laois last week, and the team's A game looks back in place or at least nearly there.

But before discarding the evidence of the league completely there are areas of potential concern for Mayo.

Principal among these is the centrefield equation. Seán Cavanagh has re-established the momentum that made him young footballer of the year 12 months ago and is again showing the boundless energy and intuitive judgement that gets him onto the end of so many goal chances.

In Castlebar he had an industrious afternoon and Ronan McGarrity struggled to contain him and Kevin Hughes. The Mayoman's basketball grounding - three years in the US - gives him athleticism and mobility but not necessarily the instincts to track someone like Cavanagh for the afternoon.

Given that David Brady for all his virtues lacks that necessary mobility, the feeling in Mayo is that wing forward James Gill, possessed of similar attributes, will pick up Cavanagh.

It's not beyond Mayo's defence to cope with the champions but they need to avoid the laxity that was on display in both of the last matches. It's hard to imagine if they give Tyrone the six-point start they gave Galway that anything but disaster beckons.

But the cockpit of the match is likely to be the other end, where Mayo's hitherto impressive attack will have to withstand constant harassment and swarm defence.

It's not a hopeless task. Kieran McDonald, whose return has radically altered the forward potential, is strong enough to ride the physical challenge and should be inspired by some of his Croke Park displays (although not his input to Mayo's last appearance here, against Cork two years ago). But the jury's still out on whether he actually will deliver.

Elsewhere is encouraging. Trevor Mortimer's style seriously bothered Tyrone last March and if he can achieve similar impact, Mayo will get chances. His brother Conor had to adapt to the physicality of Tyrone's approach in last year's under-21 semi-final and held his own. Senior is a step up but he has the credentials.

Nonetheless, it's asking a lot to expect Mayo to build a winning score against a defence that has conceded 0-10, 0-11 and 2-4 in its three qualifier outings to date.

The more plausible scenario is that Tyrone's rampaging centrefield will help create the usual quota of chances and take enough of them, either before or after Peter Canavan gets a run, to set up a likely repeat of last year's All-Ireland against Armagh, this time in a semi-final.