Predicting the outcome of tomorrow's Guinness All-Ireland hurling final is extraordinarily difficult. It's not that there's a wealth of contradictory indicators but because such doubts exist over the quality of the evidence.

Galway have absorbed the history of a quarter of a century and know one good semi-final doesn't clinch the argument for a final. John Connolly, the most distinguished of the county's trail-blazers in the 1970s and now a selector, knows this well.

During a media night interview, he pondered the reliability of one match's evidence and mentioned the phrase "tried and tested" on three occasions - twice to indicate Galway weren't and once to point out that Tipperary were. We know that mentors talk up the opposition but the phrase seemed to crop up spontaneously, suggesting at least a subconscious concern.

The strong probability is a county able to reach an All-Ireland final on the basis of one good performance doesn't know enough about itself. But what's the alternative? Michael McNamara, the trainer whose arrival from Clare has been widely credited with toughening up the natural talents of the Galway men, acknowledges the paradox. "If you don't put in a good performance in the semi-final, you don't get to the final."

Connolly's words were addressed critically at Galway's lack of matches. "The trouble from our point of view is that all our lads had a good day the last day. But what happens if the game goes against them? If you'd three or four games you'd learn more about players because the next day they might be found out."

In a modern context, when's the last time a team came from nowhere to win an All-Ireland? Cork in 1999 is one suggestion. But Jimmy Barry-Murphy's team beat three of the previous year's All-Ireland semi-finalists en route to the final, at which point they defeated the fourth.

Kilkenny's experience is more the norm. Even with Brian Cody in charge, it took an All-Ireland defeat before the team became the juggernaut of a year ago.

Tipperary, on the other hand, have been building towards this chance. The team's defeats in the past two years under Nicky English have been hard, gut-wrenching affairs: getting drubbed by Clare in a replay (as coincidentally Galway were the same year) and being edged out by Galway in the quarter-final 13 months ago.

If teams learn from defeat, Tipp have the diplomas.

Even under new management Galway learned as a county from last year's defeat by Kilkenny. They were tighter and more relentless but they were also substantially changed. Again John Connolly's reservations apply. What are this team's pressure points? How will they handle adversity - assuming it will arrive at some point of tomorrow's match?

Within the counties the atmosphere seems different. Tipp concluded their training to an ovation from 5,000 supporters. Galway, stung by the low support in the semi-final, avoided their public. Rather than ask for players to be allowed space in the run-up to the match, the management issued a statement. Bothering the team for tickets was sabotaging the county's chances. Sabotage? Yikes.

Back to the field. The starting point, as Galway surely know, is Kilkenny were abysmal in the semi-final. Whether the glass is regarded as half-full or half-empty depends on whether you regard winning comfortably with 14 men or winning by five points despite dominating the match as the semi-final's most salient feature.

Certainly, the full back line controlled the match even after Gregory Kennedy's departure but as with all recent snuffings-out of Kilkenny's full forwards, the damage was done further out. None of the full backs were under constant pressure. Ollie Canning, you feel, can rise to that as he did a year ago in more testing circumstances against Kilkenny.

But will Kennedy keep his composure and can Michael Healy, who found Geoffrey McGonigle a bit of a handful in the Derry quarter-final, adapt to Declan Ryan's comparable - if not quite similar - physical challenge.

There must be some concern about the Galway half backs. John Power did too well on the 40 for Liam Hodgins's comfort and a better marksman would have taken Derek Hardiman for a couple of early points, given the sort of space Stephen Grehan found on the wing.

Tipperary look a better team up to centrefield. That sector isn't as vital in Croke Park when it comes to winning possession but all four central players are acquisitive and good hurlers. Yet if everyone plays their own ball, you'd fancy Dunne and Enright to do more damage with the possession.

The pendulum swings in the respective attacks. With Kevin Broderick back in blistering form, Eugene Cloonan hardly able to stop scoring and Joe Rabbitte a superb target man - wherever he plays - there are menacing performers up front for Galway.

Yet Tipp have the best defence in the championship. Their biggest lapse came on a first trip of the year to Croke Park, in terrible conditions with a slippery ball. Wexford may have got three goals that day but didn't look remotely likely to repeat the dose six days later.

In the semi-final Kilkenny's backs weren't what they were or what they had looked in Leinster. Eamonn Kennedy's failure to impose himself at centre back was the most obvious decline but the indecision in the deployment of the spare man - in marked contrast to Tipp's Paul Kelly the previous day - was another.

It has to be said, of course, that Tipperary's attack has been the team's least consistent unit. It oscillates between impressive and ineffective. Brian O'Meara's absence removes a key presence from the half forwards but Eugene O'Neill's recaptured form balances the loss.

The configuration of the Munster champions' attack may be for guidance only but the options exercised in the selection may well be manifest at some stage. Eoin Kelly is at home on the wing but he has played this championship in the right corner. Lar Corbett has been training on the wing. Declan Ryan has been whispered about in the corner. Whatever.

The point is they have all scored well at various stages, with the recent exception of Corbett. Equally, they have faded in every match. Most importantly, they have done enough to pull around matches before the final whistle.

They look capable of putting more pressure on Galway's defence than Kilkenny managed and turning that pressure into scores. The instinct here is they will put up a better total than Tipperary's defence will allow their highly-rated opponents.