Willie Miller: Arnason error meant there was no way back for Dons

Aberdeen's Kari Arnason after his side go 2-0 down

Aberdeen knew Motherwell’s two strikers were going to ram-rod them at Hampden but they failed to show their class defensively.

If you are sharp mentally and have that quality and experience you should be able to handle that kind of attack.

However, the Dons didn’t which is precisely why they are out of the cup and Motherwell are going to the final next month.

All three of Motherwell’s goals came from defensive mistakes which will be particularly frustrating for manager Derek McInnes.

For the Steelmen’s opening goal there was a claim for hand-ball from Richard Tait after a Kari Arnason header spun into the box – however, that should not detract from just how badly Aberdeen defended that situation.

Defensively Dominic Ball was in a bad position to deal with it and he then stopped playing and held his hand up to call for the foul. That allowed Tait the time and space in the box to pick out a pass to Curtis Main to score.

Aberdeen then lost a second goal within minutes of that initial set-back.

To lose two goals in quick succession was extremely disappointing.

Stand-in skipper Scott McKenna slashed his clearance and then Arnason fell under pressure from Bowman.

Keeper Joe Lewis should have done better as Bowman’s shot cannoned off his chest.

After losing two quick goals the Dons never looked like recovering it. If Stevie May had taken his chance at the end of the first-half it might have been different – but I doubt it.

There was absolutely no way back when another defensive error, from Arnason, let in Main to make it 3-0 in the second half.