But the Kiwi, who came on as substitute against the Gorgie side, put a positive spin on the shock defeat.

He said: “It was disappointing to be beaten by Hearts. We would have liked to have progressed in the cup but we just have to move on - you’ve got to.

“We are out of one (domestic) competition, now we’ve got to concentrate on the other two. The manager told us that although we don’t have as many points as we had this season, he is happier this time round, so that is an indication that we are doing the right things.

“Maybe we’ve had a few slip-ups here and there but we are going to try to put a little run together.”

Killen is looking for supporters to return to Parkhead and spur Celtic on to victory in their crucial Champions League clash with Benfica next Tuesday.

Only 21,492 turned up at Celtic Park on Wednesday night but Killen is certain that a full house at Celtic Park against the Portuguese side will make the difference.

He said: “We go about our business whether there is 50,0000 or 5,000 watching.

“But obviously it does help when you have a big crowd behind you. When you need an extra lift sometimes the crowd can help you.

“We don’t have to say anything to get the crowd there (against Benfica) because on European nights they are up for it and so are the players. We know the fans are going to be there so it’s just a case of applying ourselves right.

“As everyone knows, we’ve struggled away from home but we have a decent record at home. We obviously feel more comfortable playing at home in front of our fans and hopefully we can get the result that we need.

“You can never write yourself off but a defeat will put a big dent in our campaign hopes. I don’t think it is do or die but we do really need a result.”