Ange Postecoglou's boys came out of the traps quickly against Real Betis that night, two goals up and cruising before a half an hour was played.
The only thing that pierced the silence of the Seville crowd was the incredulous jubilation of the visiting Celtic support.
With an injury-affected team, this was their new manager's first group stage game in Europe - Europa League, September 2021 - and he was owning it, until he wasn't.
Tottenham fans might have a sense of how this story ends. Two-nil Celtic became 4-3 Betis.
That was the first such lightning strike of Postecoglou's time in football management in the UK.