Their bonkers 6-6 aggregate draw with Leonardo Jardim's side consigned Pep Guardiola to an early Champions League exit on the away-goals rule, and though it might not prove as memorable as the aforementioned defeats, it has prompted another debate about the exact strength of the Premier League.

The statistics did the rounds on social media quickly after full-time. In the past five seasons, England have provided just four Champions League quarterfinalists. Compared to Spain (15) and Germany (nine), it's a particularly poor figure, with France (six) also ahead. Italy (three), Portugal (two) and Turkey (one) complete the lineup.

In basic terms, it's a damning statistic, but inspect the numbers further, and a more significant pattern becomes clear. England's four quarterfinalists have been four separate clubs: Manchester United, Chelsea, Manchester City and now, incredibly, Leicester City.

Only Spain can match that tally, with Germany (three), France (two) and Italy (one) trailing in the Premier League's wake. This is an important measure, because it underlines the variety of clubs capable of challenging in Europe's elite competition. Spain's and Germany's dominance is a reflection not of the quality of the league overall but, rather, of the staggering dominance of its bloated, all-powerful super clubs.

Barcelona, Real Madrid and Bayern Munich have all qualified for the Champions League quarterfinals in each of the past five campaigns, while Atletico Madrid have made it four in a row. La Liga has reached ludicrously uncompetitive levels; Barca and Real now finish with goal-difference figures of around 80-plus per season, which reflects the fact that they aren't just winning a lot of matches -- they're winning them by a crazily healthy margin.

Bayern's situation is slightly different, but they've also reached an almost untouchable status domestically, helped by their insistence on picking off the best players from their major rivals, Borussia Dortmund. They did exactly the same when challenged by Bayer Leverkusen at the start of the 20th century, and for all of the marvellous features of the Bundesliga -- low ticket prices, fan-owned clubs and an emphasis on developing youth talent -- it's impossible to ignore that there is one enormous behemoth eating the other 17 clubs for breakfast.

These clubs' domestic dominance means they win games at a canter and can rest players more, take their foot off the gas if the league title is beyond them and tactically focus on upcoming Champions League tests.

Man City's bonkers 6-6 aggregate draw with Monaco has prompted another debate about the strength of the Premier League.

The continual requalifying for the Champions League, of course, also means they boast great experience in the competition. Few sides excel during their first European adventure -- though Leicester City are, as ever, doing their best to disprove a general rule -- as the likes of Dortmund, Liverpool, Manchester City, Juventus (under Antonio Conte) and Tottenham have demonstrated. Going further back, it took Manchester United time to crack the Champions League in the late 1990s. It's a different style of football, and being in the tournament repeatedly taught them invaluable lessons.

The huge competitive advantage of Real, Barcelona and Bayern feels particularly blatant at the moment. Around four years ago, these clubs excelled not simply because they had wonderful footballers but also because they were tactically intelligent, highly organised and therefore extremely efficient in European competition.

Now, none of the three is, by their lofty standards, a particularly good side. For all the brilliance of Barcelona's comeback against PSG, they got themselves into a state with a truly dreadful defeat in Paris. Real aren't entirely convincing under Zinedine Zidane, who has yet to prove himself as a tactician, while Bayern don't feel quite as thrilling under Carlo Ancelotti as they did under Guardiola. There are unquestionably more tactically impressive, cohesive sides in Europe this season: certainly Diego Simeone's Atletico, probably Jardim's Monaco and perhaps Thomas Tuchel's Dortmund. Yet it's Barcelona, Real and Bayern who are currently the favourites for the competition. They've worked themselves into seemingly unassailable positions thanks, in part, to the huge inequality within their domestic leagues.

The Premier League has, of course, dominated the Champions League before. From 2008, it was rated as UEFA's best league, according to its coefficient system, which measures European progress from a country's various representatives, and it remained there for four years. During that period, England regularly contributed three of the Champions League's semifinalists.

But this proves the point: Premier League sides performed so well because they enjoyed the benefits of a frustratingly unequal league.

Between 2004-05 and 2009-10, the same four clubs -- Arsenal, Chelsea, Liverpool and Manchester United -- were England's Champions League representatives every time. They swept up the Champions League money every season, reinvested it in their squad, maintained their dominance over the other 16 sides in the division and repeated the process.

Although the Premier League could take pride in its European performance, the league itself was dreadfully predictable, as tedious as the Premier League has been since its formation in 1992. This spell ended in 2010, when Liverpool dropped out of the top four. Since then, the four best sides have never remained constant from one season to the next, nor has the title been defended, and while there have been a couple of runaway victors -- as is the case this season -- the league has generally been thoroughly entertaining.

The Premier League yearns for two things. First, to be regarded as Europe's best league. Second, to be a league in which anyone can beat anyone. But evidence from both the Premier League the past 15 years and across Europe today suggests these two concepts are incompatible.

It's unquestionable that individual clubs have underperformed the past couple of seasons; Arsenal remain entirely frustrating, and City's failure shouldn't be ignored, either. But while Spain and Germany are contributing more regularly to the Champions League's quarterfinalists, this owes much to domestic inequality. That, as much as anything else, is why Premier League sides have slipped back.