Five years ago, on the right or wrong day, it seemed like the six best teams in the world might stay that way forever.
In Pep Guardiola's second season, Manchester City were in the midst of a run toward 100 points, a Premier League record. Juventus weren't far behind, winning 95 points and their seventh straight Serie A trophy. Bayern Munich took down the Bundesliga by a 21-point margin.
Paris Saint-Germain had wrested control of Ligue 11 back from AS Monaco by signing Kylian Mbappe and Neymar before they began their campaign; it was only a matter of time until that turned into global domination. And Barcelona did what they almost always did while Lionel Messi wore the Blaugrana: they won LaLiga, for the seventh time in 10 years. Throw in Real Madrid, who also did what they almost always do: lose LaLiga, but win the Champions League, finishing third in their own country while simultaneously lifting the European title for the third year in a row and the fourth in the past five.
In the midst of that kind of across-the-continent dominance, it was really hard to imagine any kind of different future, and while some things have remained the same -- Bayern have an 85% chance, per FiveThirtyEight, of winning their 11th straight Bundesliga title -- the landscape looks quite different today. The Premier League is the dominant league in the world; two English teams other than Manchester City have won Champions League titles over this five-year stretch. Juventus haven't won Serie A since the first year of the pandemic; they're currently in seventh. PSG lost another league title, this time to Lille, and have routinely embarrassed themselves in Europe.
As for the two teams facing off in El Clasico this weekend?
Madrid lost Cristiano Ronaldo and Gareth Bale, the two biggest stars from their famous front three ... and the 30-something third-wheel, Karim Benzema, became a Ballon d'Or winner, driving Real to two league titles in three years and another Champions League trophy. Barcelona, meanwhile, lost Messi, and they haven't won LaLiga since before the pandemic. In each of the past two seasons, they've been eliminated ... from the Europa League.