Neil Lennon, Celtic’s increasingly embattled coach, couldn’t fail to hear the commotion as he walked into his post-match media conference.
Celtic’s players headed to Italy on Wednesday for a Europa League match against AC Milan looking for just a third win in their last 11 games in all competitions.
Even more so this season as Celtic chases an unprecedented 10th straight league title, which would close the gap to Rangers in terms of overall championship triumphs to two.
Rangers, meanwhile, is taking advantage of its rival's slump, even outdoing Celtic by rising atop its Europa League group that contains Benfica.
Stopping Celtic achieving “The 10” — as it is often referred to Scotland — is the biggest task this season, though.