Martin Dowden
BBC Sport Scotland at Pittodrie

They may be trailling but Aberdeen do deserve praise for the response when they looked lost at sea at 3-0.

They've created chances and shown remarkable confidence despite their predicament. That will please Derek McInnes but he'll know they have work to do defensively.

As Pat Bonner alluded to rather splendidly, there's more goals in this and Sinclair then Boyata almost delivered.

That Leigh Griffiths goal was his 16th strike of the campaign. Not bad for a man who has been forced to spend much of the campaign as understudy to Moussa Dembele.

Image source, SNS

Kenny Crawford
BBC Sport Scotland at Tannadice

No goals yet but a decent amount of action in those opening 45 minutes.

The highlight was a terrific diving, one-handed save by Morton goalkeeper Jamie McGowan to deny Tony Andreu's header a place in the corner of his net.

Morton had one good Kudus Oyenuga chance when he shot narrowly wide, but the Greenock men's final ball has often been wayward. They have also failed to make the most of several set-piece opportunities.

That tackle by Jonny Hayes was as good as a goal at the other end. The winger is the only player in red who can cope with the searing pace of Scotland's player of the year, Scott Sinclair. And, with the Englishman in the Reds' box and ready to score yet again for Celtic, in slides Hayes from the foggy haze enveloping the ground, just a fraction of a second before his opponent who falls to the turf. An outstanding tackle, and tremendous refereeing by Steven McLean.

BBC Scotland pundit Pat Bonner is confident he won't be eating Willie Miller's fetching woollen tammy: He roars from the Pittodrie main stand: "If there are no more goals in this game I will eat Willie's hat! It's been a fantastic game! There must have been 20 chances in this game!" 

Kenny Crawford
BBC Sport Scotland at Tannadice

Both sides know how important the first goal is in this second leg and that factor is creating real tension at Tannadice.

The visiting Morton fans are very vocal and so far stand-in goalkeeper Jamie McGowan has done everything asked of him in a competent manner.

United striker Simon Murray can turn in a flash and is really giving the Ton defence something to think about.

Craig Gordon has to be lively to save Niall McGinn's shot from eight yards. The Northern Irishman should probably have scored - his touch was good enough to afford him plenty time to compose himself. With no time to sulk, McGinn runs over to take the corner which is subsequently met by Ash Taylor, who heads wide. Derek McInnes punches the air, Andy Murray style, in frustration.

BBC Scotland commentator Rob Maclean: "It's still very delicately balanced. Morton have had plenty of the opening half hour at Tannadice but are not doing enough with the ball. (Kudus) Oyenuga is pretty much being starved of possession.

And Craig Gordon is required neither to save a shot nor start an attacking move as he collects a weak cross from Dons defender Shay Logan. The game resembles two runners in a 5000m race who went full pelt for the first 200m and are now paying the price.

BBC Scotland football pundit Pat Bonner: "Joe Lewis and Craig Gordon are great shot stoppers, but I think Craig comes out on top when they try to build from the back."

Kenny Crawford
BBC Sport Scotland at Tannadice

Lovely stuff from United forward Simon Murray there, receiving the ball from Stewart Murdoch before turning and shooting right across goal - Thomas Mikkelsen just arrived too late at the back post!

Kenny Crawford
BBC Sport Scotland at Tannadice

Still no goals but we've just watched Morton manager Jim Duffy trap a high clearance beautifully on the sidelines. He'll have been heartened by the cheer that followed.

Martin Dowden
BBC Sport Scotland at Pittodrie

Things are calming down to a mild storm after a scintillating opening period, the like of which I can't recall witnessing. 

Incredibly, some Aberdeen fans were heading for the exit at 3-0 until Hayes stepped in with a glorious strike.

If this is a taster of what lies ahead in the cup final, then it'll be one to remember. Fabulous action although Aberdeen in particular have to be better at the back.

Tom Rogic, who has scored against Aberdeen three times already this season, skillfully darts between two red shirts and smashes a shot that is too close to Joe Lewis, who makes the block.

Martin Dowden
BBC Sport Scotland at Pittodrie

It's exactly what Aberdeen didn't want with that Scottish Cup final looming on the horizon. However, Jonny Hayes has produced a magnificent finish to provide some hope. Stockley should've had another! 

It was a horrendous start for Aberdeen, particularly defensively where Celtic are already running riot.

Credit to Celtic's offensive players who look unbelievably sharp. It's deadly stuff. This could be an excruciating evening and extremely damaging for the home side unless they capitalise on Hayes' brilliance which they look capable of.

An unbelievable start to this contest.

And, would you believe, Aberdeen should be within a goal of Celtic. Jayden Stockley found space in the box, falling backwards away from his marker but still keeping his eye on the ball, but his header was just wide of Craig Gordon's right-hand post.