Dublin are right back in this contest.

Brian Howard wins a free around 15 metres from goal after being brought to ground and Cormac Costello calmly converts in front of a raucous Davin Stand.

Just a point separates the sides at Croke Park.

Dublin hit back through one of their experienced leaders.

Ciarán Kilkenny glides past Finnbarr Roarty to create the opening before confidently splitting the posts from the left-hand side.

The Dubs reduce the gap back to two points.

Donegal are beginning to build momentum once more.

After striking the post moments earlier, Finnbarr Roarty takes responsibility himself this time and lands his first score of the afternoon.

The Tir Chonaill men quickly follow up through substitute Ryan McHugh, whose point restores a three-point cushion.

Donegal come agonisingly close to adding to their tally.

Finnbar Roarty picks out Caolan McGonagle, whose effort crashes back off the upright and away to safety.

Dublin break upfield but cannot make the most of the let-off as Paddy Small's effort drifts wide.

A frantic spell at Croke Park with 42 minutes played.

Conor O'Donnell passes up the chance to restore Donegal's three-point advantage as his effort drifts wide.

Dublin quickly turn their possession into attack and Paddy Small again finds space down the right-hand side, splitting the posts for his second score in quick succession.

Just a point between the sides now.

Donegal's defensive structure is causing Dublin plenty of problems in the opening stages of the second half, with the visitors repeatedly forcing the Dubs away from scoring range.

But Paddy Small eventually finds a pocket of space down the right flank and clips over his first point of the afternoon to reduce the deficit.

The first score of the second half goes Donegal's way.

Michael Murphy calmly converts a free to extend the Tir Chonaill men's advantage and open up a three-point cushion at Croke Park.

Two significant changes for Donegal at the interval.

Ryan McHugh and Oisin Gallen, who were both late withdrawals before throw-in, have now been introduced for the second half.

They replace Max Campbell and Shea Malone respectively.

We're back under way at Croke Park.

Referee Martin McNally gets the second half started as Donegal and Dublin resume battle for a place in the All-Ireland quarter-finals.

Thirty-five minutes remain to decide who extends their season and who heads for the exit.

John McGovern
BBC Sport NI contributor at Croke Park

A pulsating first half comes to a close in front of a crowd of 32,220 at Croke Park, with just two points separating the sides in this winner-takes-all encounter.

The momentum swung repeatedly during a thrilling opening 35 minutes. Dublin looked to have seized control when Con O'Callaghan capitalised on a Donegal kick-out error to fire to the net, only for Peadar Mogan to respond in stunning fashion with a low finish into the far corner just before the break.

The Dubs will also be assessing the loss of Nathan Doran, who was forced off through injury before the half-hour mark.

Ger Brennan's side have work to do, but with only two points between the teams, a quarter-final place remains very much within reach.

All to play for in the second half.

Image source, Inpho

Armagh will face Kildare in the Ladies' All-Ireland SFC quarter-finals after beating Waterford 2-15 to 1-15 at the Athletic Grounds.

Lara Marsden and Aoife McCoy netted for the Ulster champions as they held off a late fightback from Waterford to reach the last eight.

Armagh led by seven points with nine minutes remaining, but Maeve Daly's goal set up a tense finish.

However, thanks to two points from Caroline O'Hanlon, Armagh had enough to progress to the last eight as the winners from Group One.

However, Tyrone exited the competition after narrowly losing 1-12 to 1-10 to Meath.

Meadhbh Byrne scored 1-2 for Meath at Healy Park as the Red Hands fell short despite Maeve Maxwell's penalty.

Donegal were also on the end of a 1-15 to 2-6 defeat by Mayo and both Ulster counties will drop into the relegation play-offs on 4 July after they finished at the bottom of their groups.

If Armagh can beat Kildare on the weekend of 4-5 July, they will face either Galway or Mayo in the semi-finals.

Holders Dublin will take on Cork and Kerry with face Meath in the other last-eight ties on the other side of the draw.

What a response from Donegal.

Colm Basquel passes up a chance at one end with another effort drifting wide before the Tir Chonaill men break at pace from their own kick-out.

Peadar Mogan again finds himself with acres of space down the right flank and when the ball arrives, the corner-back drives a low effort across goal and into the far corner of the net.

A clinical finish from Mogan and Donegal hit back immediately to regain the lead as we head towards half-time.

What a half of football at Croke Park.

A huge swing in momentum at Croke Park.

Con O'Callaghan's initial effort drifts wide, but Donegal goalkeeper Gavin Mulreany's short kick-out goes straight to Niall Scully.

The Dublin forward pounces on the mistake and immediately feeds O'Callaghan, who makes no mistake this time, rifling the ball to the net.

With less than four minutes remaining in the first half, the Dubs have turned the game on its head and lead for the first time since the opening quarter.

Colm Basquel tries his luck from distance but the ambitious effort drifts wide as we approach half-time.

Play is then halted with referee Martin McNally speaking to Shane O'Donnell while Dublin defender Nathan Doran receives medical treatment.

Doran's afternoon is over after 29 minutes, with Eoin Kennedy introduced in his place.

Conor O'Donnell's effort drifts wide and Dublin quickly turn defence into attack.

Niall Scully finds space down the right flank and calmly fists over the bar, reducing Donegal's lead to two points.

Shane O'Donnell powers through the Dublin defence before laying the ball off to Michael Langan, who continues his impressive start by converting his fourth point of the afternoon.

Dublin respond immediately from the kick-out. The ball is worked into Cormac Costello in front of goal, but rather than go for goal, he takes the safer option and clips over the bar.

A much-needed response from Dublin.

Brian Howard gets the Dubs moving again before Con O'Callaghan follows up with his second score of the afternoon to cut the deficit back to a single point.

The hosts are back in touch after Donegal's recent purple patch.

10 minutes remaining of this half.

Donegal are beginning to take control around the middle third.

Peadar Mogan passes up a promising goal chance, but the Tir Chonaill men retain possession from the resulting kick-out and Shea Malone opens his account for the afternoon.

Moments later, Donegal win another Dublin restart and Michael Murphy punishes them again, extending the visitors' lead.

Michael Langan is enjoying a fine opening quarter.

Michael Murphy does well to hold off his marker before feeding Langan, who keeps his composure and splits the posts for his third score of the afternoon.

Donegal edge back in front at Croke Park.

Colm Basquel finds space from distance and decides to take the score on himself, making no mistake to bring Dublin level once again.