It is not always obvious, in the presence of brilliance, to realise quite the scale of what is unfolding. The people who saw the Beatles play their first gigs probably thought they were promising enough without quite concluding that here were four young men who would change the world.
Last night, orchestrated by Lionel Messi, the finest footballer in the world, Barcelona entered a claim to be considered the best club team that has ever played the game. The sharp combinations of Messi, Xavi Hernández and Andrés Iniesta make the game mesmeric as well as beautiful.
There are plenty of other worthy candidates for the title. In Britain, all 11 of the so-called Lisbon Lions who won the European Cup for Celtic were born within a 30-mile radius of Glasgow. There is the Liverpool team that dominated the 1980s, the Manchester United team of Charlton, Best and Law or the 1999 treble winners from Old Trafford. The 2004 Arsenal team were the first since Preston North End 120 years earlier to go through the whole season undefeated.
Perhaps none of the British teams can rival the 1989 AC Milan team that was inspired by Gullit, Rijkaard and Van Basten, or the Real Madrid team of 1960 that was carried to a fifth successive European Cup victory, on the genius of Di Stefano and Puskas, in one of the greatest games of all time, against Eintracht Frankfurt in Glasgow.
But if greatness is an equation that is the sum of style and success, Barcelona are on the way to the title of the greatest of all. Already the holders of their domestic championship and the 2009 Champions League winners, Barcelona are well placed to win both titles again. To do so with such panache is elevating them to the highest level.