Celtic boss Ronny Deila has labelled two members of his squad "unprofessional" for squabbling over who should take a penalty.

The incident took place during the Bhoys' straightforward victory against Stjarnan in the second qualifying round of the Champions League on Wednesday night.

Stefan Johansen and Leigh Griffiths argued on the field over who would take the spot kick, with the latter eventually seeing his effort kept out by Gunnar Nielsen.

Asked what had transpired on the pitch, an irked Deila told BBC Sport: "I don't know, I have to ask them. It's very clear who's going to take that penalty; the guy who took the penalty.

"Leigh has taken penalties before so that is quite clear. We can't have it like that, it's unprofessional."

Celtic went on to beat the Icelandic minnows 2-0 ahead of next week's return leg.