Last night, the watching world saw Barcelona's Lionel Messi at his supreme best once again.
There was no need for debate (although there was plenty of it nevertheless), no need even for description, just appreciation of a true great at work.
But it also threw up a timely reminder to Celtic fans that this footballing demi-God is beatable, for the Bhoys have beaten him and his mighty Barcelona side.
Indeed, Beram Kayal clearly hasn't forgotten, with the ex-Celtic man taking to Twitter and Instagram with disbelief about the events of 2012.
The Hoops beat Messi's Barcelona 2-1 at Parkhead in the Champions League group stages, despite a late Messi consolation goal. Celtic were also only narrowly beaten by the same scoreline at Camp Nou.
And, although Kayal was only a substitute in both games, the 27-year-old could not help but look back at playing his football within several feet of the magical Messi.
Celtic fans clearly made an impression on Messi that historic day in Glasgow - but it's certainly the Argentine leaving a lasting impression on anyone that watches him these days (just as he has been doing ever since he first kicked a football).
Sadly, Messi also left a lasting impression on Bayern defender Jerome Boateng on Wednesday night...