Celtic skipper Scott Brown cannot be out on the pitch when his side bid to reverse a three-goal deficit against Legia Warsaw, but he will be in the dressing room beforehand calling on his team-mates to show the same spirit and belief that pulled them out of a similar hole last season.
Ronny Deila suffered a difficult start to his Celtic career when the manager lost Brown to a torn hamstring literally seconds into his opening pre-season game.
And the pressure intensified when Celtic capitulated in Poland last week, seeing Efe Ambrose sent off in a 4-1 defeat in their Champions League third qualifying round first leg encounter.
Legia also missed two penalties, and whether that merely saved Celtic from utter humiliation on the night, or whether it ultimately rescued their Champions League hopes, will become clear at Murrayfield on Wednesday.
Celtic suffered another painful European defeat last season, in the fourth qualifying round against Shakhter Karagandy, but Brown and his colleagues recovered to overturn a 2-0 defeat at Parkhead.
And the midfielder had an instant response when asked what the key to their comeback was.
"Spirit," he said. "Everyone believed we could do it. We knew we were a better team than we showed over there and I'm sure the lads will be thinking that as well.
"We have a point to prove. Can we go out and do it again? I believe we can.
"It always hurts when people write you off, but that's football. People always write you off. That's when you have to put the wrongs right and go out there and show everyone what you can do.
"You can prove a point to everyone out there on the field."
Deila's task in forging a relationship with his squad has no doubt been hampered by losing his captain to injury for up to three months, but Brown will provide a rallying cry in Edinburgh.
Speaking at the home of Scottish rugby, he said: "I've been on the training field as well, I've been with the lads.
"My main priority is to get back as soon as possible but I'm trying to be there to help the lads out all the way.
"I'll be here early doors and in that changing room with the lads trying to help out in any way that I'm needed.
"But the gaffer has got it down to a tee. He knows what he wants, he knows what he believes in. It is a work in progress but we can put it right on Wednesday."
When asked what message he will give his team-mates, he said: "Believe in yourself, remember what we did last season, what a good occasion it was and how good a night it was, and go for it."
The win over Karagandy was one of the great European nights at Celtic Park, which is still out of commission following the Commonwealth Games opening ceremony, but it remains to be seen how good the atmosphere is at Murrayfield.
Brown said: "Celtic Park's a great stadium, especially with 60,000 fans chanting. But I'm sure we can do it at Murrayfield as well.
"They were outstanding at the last game when there were 40,000 there. It shows how great and loyal they are.
"There was a great atmosphere and hopefully Wednesday night is going to be the same. When the fans get behind us it's a 12th man and it puts a lot of pressure on teams as well.
"We did it last season against Karagandy and the fans were outstanding from start to finish."