Jurgen Klopp looked at the assistant referee in front of the Sandy Jardine Stand and then glanced over his shoulder at the fourth official, with a hint of trepidation.
He was waiting, tentatively, to see if there was a reaction from either man but neither flinched.
And, then, after what seemed like an age, Klopp began to smile, clapping his hands slowly at first before he knew it was safe to celebrate.
It had been hard work in Glasgow, too hard at times, but Darwin Nunez had just scored Liverpool’s third goal and Klopp knew that a huge step towards the Champions League knockout stages had been taken — one point from their final two games and last season’s finalists will be in the last 16.