All-Ireland SF quarter-final/Dublin v Donegal, Croke Park, 4.15, Network 2: After the sky blue euphoria already witnessed in Croke Park this season, all the winter talk of two county teams for the capital seems a little frivolous.Not since the Heffernan era has Dublin been so united and so irresistible. Keith Duggan reports

A young city team is playing fresh and innovative football and, on the sidelines, Tommy Lyons is talking up a storm.

The Dubs are in vogue.

Today is of massive importance to the city team. They are the biggest sporting draw on the island by a considerable distance and the thousands that will leave the suburbs for Jones' Road will do so with great expectations.

Donegal present a complicated proposition for Dublin however. For all the anniversary reminiscences about 1992, their mutual history makes for a slender volume.

The intense rivalry and hard lessons that Meath and Kildare inflicted on the Dubs in recent years are not available as motivational tools here.

But the blues on the Hill and in the stands will expect their team to sweep the Ulster visitors with the same conviction that preceded that match 10 years ago.

To an extent, both teams have already achieved considerable progress this year. As Lyons has pointed out, Dublin's Leinster title victory is of merit in its own right and, regardless of what may happen for the rest of the championship, it renders his first campaign a success.

Against that, as the contenders begin to fall away, the notion that the Dubs will not have as good a chance to win the All-Ireland again may be beginning to materialise.

Should they get to the All-Ireland semi-finals, the remaining action becomes clear-cut and monumental. But first comes this sticky and tricky 70 minutes.

Donegal have coyly come to the city with their caps in hand and eyes full of wonder. No pressure.

The brave victory over Meath was borne of the desperation not to throw another big game away, a habit that had begun to haunt the county.

They held their nerve, played reasonably well, and will now believe like never before.

Brendan Devenney and Adrian Sweeney are rightly identified as being the key for Donegal and the Dublin defence has not yet faced such a dynamic forward pair as Ollie Murphy was injured when the city team played Meath.

But it is significant that Donegal's support forwards such as Brian Roper and Michael Hegarty have grown in stature over the summer.

It may be that they will trouble Dublin as deeply as the star turns.

At midfield, Dublin have a physical advantage in Ciarán Whelan and Darren Homan, but will have to work to counter Donegal's frenetic work rate in that sector of the park.

Dublin also have the discovery of the season in young Alan Brogan. His brilliance against Meath was a sweet surprise, his composure in the Leinster final awesome.

Now, however, the novelty is gone and he will be judged by the superlative standards he has set.

For Dublin have needed Brogan's wonderful contribution and a series of perfectly timed goals from Ray Cosgrove that nobody saw coming before the season.

Dublin have been living by goals this season and, if the day arrives that the goals just don't come, the pinch can be fatal.

Their strike-rate has also glossed over an erratic record from free-kicking, something that again catches up with a team sooner or later.

Donegal's chief problem is their collective lightness and their obsessively patient build-up play, which sometimes lands them in hot water.

Dublin could make hay through their sizeable half-forward line, but Ray Sweeney and Kevin Cassidy, especially, have rarely been bettered so far. And Devenney's reputation shines on from his previous summer's work for he has been industrious this year, but not yet at his best.

Kildare's disintegration against Kerry has led to a revision as to the worth of Dublin's Leinster march. But such evaluations are often unfair.

The fact is that Dublin came through a tight game, a feat that eluded them for a number of seasons.

The likelihood is that Donegal, unless they get a blast of nerves, will present them with another tough and close game that could go to the very edge.

There is a gnawing feeling about Dublin that it has all happened a little too smoothly so far. Sooner or later in sport, the small breaks stop happening. If they desert Dublin today, then Donegal have developed enough ruthlessness to guide themselves through.