Sam Cosgrove was frustrated the Dons couldn’t show what they were capable of against Celtic after ending the Scottish Cup semi-final with nine men.
Aberdeen were beaten 3-0 by the Hoops at the national stadium as their hopes of lifting the Scottish Cup for the first time since 1990 were abruptly ended.
Dom Ball was first to be sent off near the end of the first half.
The Rotherham loanee collected a second yellow card following a clash of heads with former Red Ryan Christie, after a harsh booking for a trip on former Don Jonny Hayes.
In the six minutes of injury-time at the end of the first period – added because of Christie’s treatment – James Forrest fired Celtic in front.
Just after the hour Odsonne Edouard’s penalty made it 2-0 and then referee Craig Thomson gave Lewis Ferguson a straight red card for a two-footed lunge on Tom Rogic.
Dons boss Derek McInnes and assistant Tony Docherty were also sent off – with McInnes dismissed after Rogic netted the Hoops’ third.
Striker Cosgrove was disappointed that the red cards for Ball and Ferguson suffocated any hopes of Aberdeen mounting a second-half comeback.
The Englishman, 22, said: “The first emotion that comes to mind is frustration and then annoyance.
“We came to Hampden knowing it was going to be a tough day and I’m sure Celtic expected the same. But when we go down to nine men, especially at two goals behind, it was always going to be a tough task.
“We knew it would be a tough game with 11 men on the park.
“I felt the gameplan was going pretty well up until the first sending off. We had frustrated Celtic, it was five minutes to half-time and then to get a man sent off and lose a goal was extremely frustrating.
“I thought Dom’s first yellow was harsh and could have been waved on. There were a few challenges going around in the game and it wasn’t a persistent foul – it was a harsh yellow. The second one was an incident which can go either way.
“They both collided and Ryan has come off worse – firstly I hope Ryan is all right. But it was harsh overall on Dom.
“And it’s just a rush of blood to the head from Lewis. You can’t say ‘fair enough it’s happened’ but you can understand.
“Sometimes emotions get the better of you. It was a very frustrating day for Lewis and that topped it off.”
McInnes was dismissed for making a gesture at the Celtic support in response to a sectarian chant being aimed at him from the stands.
No2 Docherty was sent off for remarks made to ref Thomson at half-time.
Cosgrove was unaware of what had happened with McInnes’ sending-off and added: “I’ve not got a clue what happened with it. I heard that Tony Docherty maybe got sent off at half-time.
“But I don’t know what else happened. In these games you definitely need the rub of the green and we don’t feel like we got that.”
All the Dons have left to play for this term is a Europa League qualifying spot.
They trail Kilmarnock on goal difference in the battle for third but Cosgrove has backed them to finish strongly in the Premiership and secure Europe for the sixth straight season.
The 20-goal hitman said: “There was a lot of annoyance and frustration throughout the dressing room at the end.
“The whole city and club had hopes going into the game and they’ve come crashing down in very annoying fashion. But we’ve got to dust ourselves down for the rest of the season.
“It won’t be too hard to rally because it’s a great bunch of lads in the squad.
“We’ve got to have some time to reflect on this and we will be disappointed. We will definitely come back, though, and we’ll be back strongly on Saturday.
“The spirit in the squad will be important and there’s no doubt it will be there.
“We do need a bit of time to reflect and be disappointed. But when we’re back training we’ll be up for it and the games coming up.
“It’s now about getting as many points as we can from the remaining games to get the points we need to secure third place.
“We don’t want to let the season peter out and not qualify for Europe.
“And we are still right in among it and we’re very focused and determined to get into Europe.”