Arsenal fans will always tell you that their 2003-04 season was the greatest in Premier League history - if not the best ever in European football. That team, one of Thierry Henry, Dennis Bergkamp, Patrick Vieira, Sol Campbell and more, went 38 games of a Premier League season without losing. And although critics can point to the glut of draws Arsene Wenger's side ground out, there is no discounting just how remarkable that achievement was.
That was the last time a team in one of Europe's top-five leagues went undefeated across the course of a league season. It is still spoken about today, golden commemorative trophy and all. Unfortunately for the Gunners, though, a better, more impressive campaign is coming to a close - this time on the continent.
Xabi Alonso's Bayer Leverkusen are two wins away from completing a remarkable invincible season. They have already won the Bundesliga by 17 points, and did so without being beaten. Come out on top in their last two fixtures of the campaign - the Europa League and DFB-Pokal finals - and they will have complete a remarkable treble.
Given the context, the budget, the manager and the landscape of both German and European football, Leverkusen's season should be regarded as being better than all of those great campaigns to come before them. Forget Arsenal 2003-04, or Barcelona 2008-09, or Manchester United 1998-99, or Inter 2009-10 or Manchester City 2022-23. This season, one that is on the cusp of going 53 games unbeaten, would be the greatest in modern football history.