There are so many similarities between Cork and Mayo as they line up for tomorrow's Bank of Ireland All-Ireland semi-final at Croke Park that it is a particularly hard match to call. Both sides were surprise winners in the Munster and Connacht finals last month; each has a strong defence and a suspect attack.

Even the distinguishing features are balanced. Mayo have greater strength in depth but Cork are more settled. Cork are the current National League holders but Mayo have more experience at this level in the championship.

The teams' most recent opponents in the provincial finals were the two most recent All-Ireland champions, but then there is the debate as to whether Kerry or Galway were more awful in defeat.

The belief here is that Cork have the advantage and if that position is substantially based on question marks over Mayo, it's not held with absolute conviction.

There are three main arguments generally advanced in favour of Mayo: the improvement in their attack; their steady defence and the experience and motivation they take into the match after the reverses of recent years and, more distantly, the 20-point drubbing handed to them by Cork in their last All-Ireland semi-final six years ago.

In the second half of the Connacht final it took Mayo nearly half an hour to eliminate Galway's four-point lead - despite their opponents' obliging refusal to score anything in reply.

James Horan indicated that he has recovered his form of 1996 and his five points from play was courageous as he had to put a couple of bad misses behind him. But aside from this there wasn't much to support the theory of evolution.

Kieran McDonald had a strong impact when he came on but this isn't new territory. He still has to prove himself as a consistent performer at Croke Park.

Kenneth Mortimer has moved to the 40 from corner back to general acclaim but his performance in the Connacht final wasn't hectic. He's a good footballer but can hardly be expected to have absorbed the tricks of the playmaker's trade in two championship matches. David Nestor is another clever footballer whose commitment was almost incandescent in the Connacht final. But, like Mortimer, he hasn't a rack record as a scorer. Maurice Sheridan is probably the best place-kicker in the game at present but Cork's defence don't foul much.

Filter these sober reflections through the fine mesh of Cork's defence which has conceded an average of less than eight points per match this championship. Their pace and marking will test Mayo's reputed improvement.

Mayo's defence played really well in the second half of the Connacht final and their half-back line in particular excelled. Alan Roche's retention of his place was no real surprise even though Noel Connelly has regained fitness. Roche on his debut dealt with all three of Galway's half-forwards and came out ahead. Yet in the full-back line things weren't as reassuring. Kevin Cahill was superb on the edge of his square but in the corners there was trouble. Gordon Morley struggled on the pacy Derek Savage and Aidan Higgins didn't do much better when he switched.

Cork's attack is not flawless and Don Davis will have his work cut out to reproduce the form of the Munster final at full forward. Joe Kavanagh is in his best form for a while and may at some stage resume the central partnership with Mark O'Sullivan which illuminated Croke Park on those wet League afternoons in April. O'Sullivan failed to match his big total against Derry in the semifinal against Meath, but still scored three points - half the team's total. Micheal Cronin has attracted attention as a debutant tomorrow but the attack is sufficiently experienced to cope with a newcomer.

Centrefield is expected to favour Mayo with their greater reserves on the bench, but Cork's pair of Nicholas Murphy and Micheal O'Sullivan have competed all year against partnerships which looked stronger on paper.

Finally the motivation issue isn't that relevant. Few players survive from the 1993 match and experience is a double-edged sword as John Maughan admitted this week when pointing out that Mayo performed best in 1996 when they were least experienced.

There will be little in it but Mayo are slightly more suspect and Cork have sufficient equipment to exploit that.