All-Ireland SFC Semi-final/ Mayo1-16 Dublin 2-12: Ciarán McDonald has always prompted great discussion. Even this season the question of how deep he plays and how deep he should play has absorbed many football people. Like many another inscrutable artist, McDonald has contributed to the enigma by keeping a low and silent profile.

But if ever anyone let their football do the talking it was the blond Mayo playmaker. After a final quarter played very much the way he likes it - Mayo in control and needing to dampen the tempo of a match - he had secured possession and moved the ball thoughtfully before the game-breaking moment arrived in the 68th minute.

Supplied by Kevin O'Neill on the left wing and facing into a by now extremely agitated Hill 16, McDonald's eloquent left foot spoke and it was just what Mayo supporters in the 82,148 capacity crowd wanted to hear. The point that curled over the bar would win the match.

And so the great test came to pass. But in the end for all the pre-match talk of Dublin not having been examined properly and needing rigorous checking of their credentials, this explosive and utterly memorable All-Ireland football semi-final asked the questions in a most unexpected way.

By the end the mantle of examiner had passed from Dublin's opponents to the Leinster champions themselves and it was Mayo who took the test and came up with all the right answers.

It's hard to be dispassionate after such an epic, rumbling confrontation that from before the throw-in to the final whistle swung one way and then another before stamping the Connacht champions' papers for a second All-Ireland tilt with Kerry in three years.

Dublin have been said to have adopted a more "in-your-face" approach to opposing teams this season but Mayo took the pressure and stared them back down. Before the match even started - and by their own account not entirely deliberately - the Connacht side raised the stakes by locating their warm-up down at the Hill 16 goal.

As anticipated, Dublin rose to this premature challenge and both teams practised away into the goal with some of the supernumeraries eyeballing each other and in the chaos one of the Mayo backroom team, dietician Mary McNicholas, had to be carried off after being hit by a stray ball, kicked randomly by Dublin's Alan Brogan.

Mayo's management would have been pilloried had the match gone wrong after such a confrontational start but both teams settled - Dublin perhaps to too great an extent - once the ball was thrown in.

Mayo started well, conceded the initiative a little too easily before getting swamped in the third quarter and from that unpromising position, seven points adrift nearly 50 minutes into the match, they put together a hugely impressive comeback and dismissed all the charges of flakiness that have hung around the county, as it has flirted with All-Ireland success without quite consummating the relationship over the past 10 years.

Ciarán Whelan was fortunate to get only a yellow card for an 18th-minute challenge on Ronan McGarrity - who eventually had to leave the field injured - and then had to leave the field on a protracted temporary substitution after a clash of heads with Kevin Bonner, who also needed treatment. By that stage, the 25th minute, centrefield was breaking even with Dublin beginning to edge matters.

Ironically the absence of Whelan probably contributed to a questionable tactical call by the Dublin management for the second half. Darren Magee did well in the air with Whelan off the field and at half-time it was decided to withdraw Barry Cahill from full back and institute a chain of rearrangements that saw Paul Casey drop back to the square and Shane Ryan switch to wing back with Magee remaining at centrefield.

Ryan had been playing well in the middle and his move upset the rhythm of the team as the match unfolded and Dublin's early threat to demolish Mayo was sensationally rolled back.

Mayo manager Mickey Moran, on the other hand, brought a touch of alchemy to his switches. Virtually all of his replacements worked. Kevin O'Neill came in at the end of the first half, gave a sense of authority to the forwards and was instrumental in the pre-break turnaround that saw Mayo lead by one at half-time, 0-9 to 1-5.

David Brady's experience and strength around the middle severely disrupted Dublin at centrefield whereas replacement forwards Aidan Kilcoyne and Andy Moran made significant impacts.

Dublin started slowly and were four down before Conal Keaney's scored their first point as late as the 17th minute. Keaney, who was struggling on David Heaney, still managed to end the half with 1-2 from play.

The goal turned the match in Dublin's direction in the 23rd minute. Tomás Quinn passed to Brogan, who launched one of his trademark, high bouncing solo runs before shooting for goal. David Clarke only managed to block the ball and Keaney tucked in the rebound to level Dublin at 1-2 to 0-5.

Keaney's second point should have been a goal as he was one-on-one with Clarke. Mayo also had goal chances but both Aidan Higgins, raiding from wing back, and Conor Mortimer ended up with points instead. Mortimer was otherwise having a blinder.

The key crisis came in the third quarter when Dublin outscored Mayo by 1-6 to 0-1 in the space of 11 minutes after half-time. The goal came from Jason Sherlock, a well constructed move involving Whelan, Bonner and Brogan with Jayo slapping the ball into an unprotected net.

Keaney's third point in the 46th minute made it 2-11 to 0-10. Dublin then came to a shuddering halt. The stasis began with sloppy use of possession. They would with symmetry end the match losing the final 25 minutes by a familiar 0-1 to 1-6.

Moran threw the kitchen sink at the match. Moran was brought on as a wing back with licence to follow Bonner. The scope this afforded culminated in a critical goal when the replacement finished a move started and continued by McDonald in the 51st minute. Moran's shot squeezed past Shane Ryan and Stephen Cluxton.

Points followed, gradually eliminating the lead and reversing it. Dublin's authority collapsed.

At the very end, Dublin's blond enigma Mark Vaughan came in and in the absence of Quinn saw his 45 clawed away from just under the bar having just rattled the post with an ambitious shot from the left wing.

By now there was a sense of destiny about the day and Mayo had grasped it confidently.

MAYO: 1. D Clarke; 2. D Geraghty, 3. D Heaney (capt), 4. K Higgins; 7. P Gardiner, 6. J Nallen, 5. A Higgins (0-1); , 8. R McGarrity, 9. P Harte; 10. BJ Padden, 11. G Brady (0-2), 12. A Dillon (0-4); 14. C Mortimer (0-5, one free), 15. C McDonald (0-2, one sideline), 13. M Conroy. Subs: 21. B Moran for McGarrity (31 mins), 25. K O'Neill (0-2) for Conroy (35 mins), 23. A Kilcoyne for B Moran (45 mins), 21. A Moran (1-0) for Nallen (46 mins).

DUBLIN: 1. S Cluxton; 2. D Henry, 3. B Cahill, 4. P Griffin; 5. P Casey, 6. B Cullen (capt), 7. C Goggins; 9. S Ryan, 8. C Whelan; 14. K Bonner (0-1), 13. J Sherlock (1-0), 12. R Cosgrove (0-2); 11. A Brogan (0-4), 10. C Keaney (1-3), 15. T Quinn (0-2, free and 45)). Subs: 20. S Connell for Cosgrove (51 mins), 22. D Lally for Ryan (61 mins), 21. M Vaughan for Quinn (65 mins), 25. C Moran for Bonner (67 mins).

Referee: P Russell (Tipperary).