On a day which finished knee-deep in the debris of demolished reputations, the fall of Bank of Ireland All-Ireland football champions was particularly sobering. Only 10 months after their direct and irrepressible football had rewritten the history books and their attacking style had been hailed as restoring forgotten skills to game, a more prosaic chapter emerged from Tuam Stadium.

Yesterday was a major triumph for Mayo's troupers, refreshed after a year in the wilderness, whose decline had looked to be permanent and irreversible. The team featured some excellent performances all around the field and showed nerve and resilience to overhaul what everyone in Tuam assumed was a winning position for the champions.

Mayo were hungrier and exhibited a controlled fury which all but overwhelmed the defending champions' tepid response.

No one could have anticipated the scale of Galway's collapse. A minute into the second half, John Donnellan extended their lead to four points, 1-10 to 1-6, and they looked on the verge of pulling away to a comfortable victory.

Instead it was to be Galway's last championship score of the millennium. For the remaining 34 minutes of the match, their graph dipped through a third quarter of easy command but no scoring, into a fourth quarter when they simply wilted under the remorseless pressure of Mayo.

How did the empire collapse? It's hard to identify specific triggers but John Maughan's substitutions helped to turn a trend which wasn't particularly positive for Mayo.

In the third quarter, James Horan - who gave his best performance since the All-Ireland final of three years ago when he also kicked five points from play - hit two dispiriting wides. John Casey was sent straight in on goal by David Nestor and David Heaney only to send his 53rd-minute effort lamely wide of Martin McNamara's goal.

Into this unpromising context Mayo introduced Pat Fallon at centrefield and Kieran McDonald at corner forward for the final quarter. There had been some controversy in the county about the non-inclusion of this pair in the starting line-up, but in fairness to the selection policy, their introduction turned out well-timed.

Fallon steadied centrefield which had been coming under a lot of pressure from Sean O Domhnaill and Kevin Walsh, who was very active after half-time, winning ball around his own goal as well as further afield.

McDonald created a point for Horan with his first touch, kicked one himself seven minutes later, initiated another a minute after and created a great goal opportunity for James Nallen which was scrambled off the line by Tomas Meehan. Ultimately it led to a pointed 45 by Maurice Sheridan - leaving McDonald with a point plus three assists. Both sides were obliged to make changes, albeit thoroughly expected ones. Mayo's Noel Connelly cried off yesterday morning without even fully testing his injured leg. He said afterwards that he knew he wasn't going to be alright. Alan Roche replaced him and had a marvellous debut, taming the entire Galway half-forward line in succession.

The champions had to replace full back Gary Fahy with Damien Mitchell and re-arrange their attack with Padraig Joyce starting on the 40, flanked by Jarlath Fallon and Michael Donnellan. The latter pair were huge disappointments on the day.

Last year they gobbled up between them most of the votes in the Footballer of the Year categories, but yesterday neither made a significant impact.

Donnellan never managed one of the pacy, penetrating runs which opened up opposition defences 12 months ago and seemed curiously indecisive in the face of chances. Just after the interval he managed to shake the cover, but his fisted attempt went across goal and into oblivion.

Much of the credit for this virtual shut-out goes to Mayo's halfbacks. Roche's colleagues Fergal Costello and David Heaney gave excellent displays. Heaney marked like a leech at centre back and Costello made a number of relieving support-runs up the field.

Galway shuffled their half-forwards all afternoon, but to little effect with only Joyce giving a good account of himself.

In the corners, Mayo were in more trouble with Derek Savage roasting John Morley and continuing to give trouble to Aidan Higgins when a swap was made. Kevin Cahill, at full back, was however excellent and steadied the line even before the Galway forwards went on the blink.

Mayo's much-criticised attack proved itself to be in a fierce humour. David Nestor was breathing fire, his determination and commitment to every ball highlighted by his 28th-minute goal when he timed his run onto a ball broken by Horan and finished venomously.

Having hit the net, he threw himself on all fours and pounded the ground in celebration.

Within a minute, and despite the morale-boosting rarity of a Colm McManamon point, Mayo conceded a goal themselves. O Domhnaill lofted a ball which dropped in on Peter Burke's goal. The Mayo 'keeper fumbled it and Joyce was on hand to stick the loose chance away. The champions looked in business and took a three-point lead in at half-time, 19 to 1-6.

Throughout the match, Galway's defence played reasonably well. John Divilly, having survived a car crash on Saturday, played a stormer, especially in the first half. Around him, his defensive colleagues coped, but it wasn't going to be sufficient in the face of the forwards' second-half meltdown.