But Commons, who replaced Stuart Armstrong for the start of the second half with Celtic trailing 1-0 and having had a goal by Nir Bitton controversially chalked off, was at odds with the Norwegian as to the reasons for the defeat.
"I wouldn't say it was fear," Commons said.
"I don't think we played with fear. When you've just got the one goal you're thinking that if you can get a clean sheet or draw then you're through, so it's a completely different outlook.
"They came into the game knowing that they needed a goal, whereas we were trying to do just enough to keep a clean sheet.
"But if we had come in at half-time at 1-1, when we scored from a corner, then it puts a completely different complexion on the game. But it wasn't to be.
"I think it's a stressful night because you know what's waiting for you if you get through, but coming here with a one-goal lead put a big importance on the first goal.
"It wasn't to be. They took their chances and certainly put us under pressure."
And defender Virgil van Dijk admitted uncertainty about his immediate future following their Champions League failure.
"I'm not looking for anything. It's a great place to be and they gave me an opportunity to show myself, so I'm very thankful for that," he said.
"But if the right opportunity comes and it's the right opportunity for me then I'll consider it. But I think that's what any player would do."
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