Those of us who love the Champions League already knew that it's a mercurial beast. By turns passionate, alluring, a come-to-bed-smile and fan-faring trumpets. Then, without a blink, snarling, duplicitous, dangerous and vindictive.
But this week, for the two remaining Spaniards at least, there were new levels of bruising and damage.
Barcelona and Real Madrid both led 2-0 on the night but both went out. The Camp Nou and the Santiago Bernabeu were two cathedrals of football which rocked and rolled to the strains of nearly 200,000 worshipers.
Before the denouement there would have been a very large chunk of the neutrals around the world who not only wanted a Clasico final, but who would have cogently argued that Real Madrid and Barcelona -- at least on form -- are the two best teams anywhere on the planet.
However, each side is now licking wounds that have so much salt in them that they won't heal for a long time. Wounds that will sting anew come May 19 when Chelsea and FC Bayern Munich battle in the Champions League final.
Here are five things we learned during this crazy, tense and hugely enjoyable week.
1. Ronaldo and Messi human after all
Although Cristiano Ronaldo and Lionel Messi have been scoring extraordinary numbers of goals this season (again), they are in fact normal, sentient, flesh and blood homo sapiens like you or me.
Messi missed a penalty, failed on a one-on-one chance against Petr Cech and hit the post on a night when even his magical powers began to look thwarted. By the end of the elimination at Chelsea's hands Messi had his jersey tugged up over his head as if to hide from the pain of loss. Ronaldo, too, missed a penalty -- his during a penalty shootout -- drifted out of the game, and from a strong start began to appear extremely fatigued.
What will happen now, of course, is that some critics will have no more memory, nothing better to do than to start questioning the two superstar footballers -- niggling away at previous descriptions of Ronaldo and Messi as geniuses at work.
It irks me, immensely. In both cases what should happen is that people look around the two key players and ask about service, support and backup play.
In Messi's case, he did a lot which was potentially match winning against Chelsea, but as the game ebbed away it was clear that there were several fatigued and mentally jaded teammates around him.
Having a genius on your team must be both a privilege and a test of your intelligence. If you become used to Messi resolving the team's problems every week, the temptation to give him the ball in the hope for an explosion of lightning feet must be almost overwhelming, particularly if you are tired or overawed. Against Chelsea, for one reason or another, he couldn't form the connections with Cesc Fabregas, Dani Alves, Xavi, Andres Iniesta and Alexis Sanchez which raise him to another level.
But it's immature football analysis to simply think: Barca lost -- what happened to Messi?
In the case of Ronaldo, life is pretty unjust if the Portuguese is now criticized in light of Madrid's exit because he scored only two goals. Ronaldo's game at Madrid is at its best when Los Blancos either win the ball back deep in their half and pass with devastating speed and accuracy until he is high up the pitch, or when Madrid produces elegant Barcelona-style link-play in front of goal. In each case, teammates who are quick footed and fleet of mind are needed.
On Wednesday, Mourinho's side retrenched a little bit in the second half, as we saw a lot less of Mesut Ozil, Angel di Maria and Karim Benzema. Yet it might be Ronaldo who carries the can because A) he's high profile; and B) he missed one of the spot kicks.
Unfair. If you aggregate the four games and analyze the performances by Ronaldo and Messi, it's clear to see they provided goal threat, leadership, energy and invention.
2. Never forget to "find the dope"
Graeme Souness tells the tale that Bob Paisley, the legendary Liverpool coach, always used to warn his players that when the ball went dead or the halftime break approached that they had to "find the dope." "Someone," Paisley warned, will "doze off" and start thinking about getting to the dressing room to have a cup of tea or simply relax. Liverpool's task was to be ready to take advantage of the dope's lack of attention.
Sadly, during these semifinals the Spaniards have been the dopes.
Real Madrid was easing to a 1-1 away draw last week. Just more than a minute remained when Fabio Coentrao allowed Philipp Lahm the easiest chance to cross for a goal.
In London, Frank Lampard robbed Messi with seconds before the break and Chelsea scored its only goal.
In Barcelona, Xavi didn't run with his man Ramires, Lampard beat Javier Mascherano and suddenly Chelsea was back in a game which threatened to be closed off to it. Barcelona had scored two minutes earlier, and there were seconds left to the break.
Graham Hunter is also the author of "Barca: The Making of the Greatest Team in the World," available as an e-book on the iPad, Kindle and Kobo. The printed version is available in paperback and can be ordered at BackPage Press.
Obviously Fernando Torres also scored with seconds left to go until the end of the match. But given the oddness of the situation, with Barcelona utterly desperate for the winning goal, it can be set apart from this argument.
All managers, from the schoolyard upward, preach that with the break coming, any break, what you do above all is protect what you've got. When it's a foul, a throw-in, when there is an injury, you make sure that your concentration isn't broken. Pep Guardiola and Jose Mourinho are great managers. So how do you account for world-class players dozing off and allowing advantage to be taken by opponents who are up against the ropes?
Tiredness, stress, overconfidence? It's hard to say, but there are lessons for both Real Madrid and Barcelona. They are scoring record amounts of goals this season but, often, keeping the back door locked and remaining miserly about gifting goals and chances are the tendencies that win you important victories and the great trophies.
3. How to treat defeat
I honestly try very hard to ensure that nobody thinks I have an anti-Mourinho or anti-Madrid agenda. I respect Real Madrid as a club and as an entity which has shaped world and European football. Mourinho has ample talent and is a restless, interesting and successful man. But there are times when his self-control lets himself and the reputation of his club down.
Having admitted, quite legitimately I think, that he wanted his former club Chelsea to defeat Barcelona, he wouldn't let the subject lie once both La Liga sides had been eliminated. Perhaps I misinterpret him, but my inference is that the Portuguese was talking about Guardiola when, in mean spirit, he said: "Some people think they are the masters of the game, but they know nothing about effort and spirit. They know nothing about playing for so long with 10 men. I am thinking about the heroes of Inter and of Chelsea. Next season we will be back fighting again to win the competition."
For his part, Guardiola took time last weekend to immediately congratulate Real Madrid for its Clasico win and for its title challenge all season. The Barcelona manager also couldn't have been warmer in his treatment of surprise victor Robbie Di Matteo. Mourinho managed that in his reaction to Jupp Heynckes, and it would just have been classier, less rancorous and less gratuitous without his sideswipe.
4. Remember the past
This week's events lend retrospective value to the achievements of Manchester United in 1999, Barcelona in 2009 and Inter in 2010.
One Mourinho comment which seemed kosher was that: "A little bit of the difference is that in the last weekend Bayern didn't play but we had the biggest game in our league and so they were fresher than us."
The fact to support him remains that Chelsea rested the vast majority of its starting lineup last weekend against Arsenal while Bayern Munich mimicked the tactic in what was a relatively meaningless Bundesliga match in Bremen -- only three players started that match and the one at the Bernabeu.
Real Madrid and Barcelona laid their souls on the grass at Camp Nou on Saturday night and now both of them are the surprise victims of Champions League shocks. Not even home advantage in the second leg was good enough for the two favorites.
The trend has been that it's relatively difficult to win the Champions League plus another domestic trophy, and to win all three of the big ones (CL, league and national cup) is a magnificent achievement comprising class, cleverness, a dash of good fortune and loads of willpower.
In comparison to the two beaten Spaniards, Chelsea and Bayern have had tumultuous domestic seasons. Only a handful of weeks ago, the Bavarians had to issue a press note denying they were considering sacking Heynckes, while Andre Villas-Boas not only didn't make it this far, he must be pretty sore at Chelsea's performance since he left.
The league title has been out of reach for Chelsea for some considerable time and Bayern has known that Dortmund is de-facto champions for a while, too.
Often, as was the case when Heynckes won the Champions League for Real Madrid in 1998, the problems of a bumpy domestic season can culminate in one big effort in a competition which feels glamorous, a change from league drudgery and where a reputation for greatness can be earned. However to win the League, Champions League and national cup -- as United, Barca and Inter did -- is an achievement of gargantuan proportions.
5. Is this the way in which either Mourinho or Guardiola wants to sign off?
There are offers in the marketplace for both coaches. Mostly from the same small group of elite clubs. But almost every top Italian club would bend over backward to hire Guardiola, while it's very hard indeed to imagine Mourinho going back to a championship some aspects of which he enjoyed very little. Both men spoke of their futures after being knocked out -- but Mourinho with a good deal more clarity of voice. "I'm going to continue," he stated. "If there continues to be empathy here then both this club and this team have margin for growth."
That said, "empathy" is difficult to prove. So should, say, Manchester City give Mourinho a firm offer with a big salary and a big transfer market budget to succeed Roberto Mancini, then who knows? Guardiola, for the first time, admitted that it's overdue for him to meet president Sandro Rosell and make a decision about staying or leaving. Rumors abound. Mostly there is an anticipation that Guardiola has decided to move to England, perhaps even Chelsea, but many of his players and some directors still say they expect him to renew at Camp Nou.
When Guardiola reviews this season he'll find it hard to argue that his uncertainty over staying or leaving had done anything to help his mood, focus or clarity of vision.
However, the Catalan has done such unbelievable work that if he chooses that now is the moment when he requires a fresh challenge then the fact he'd be leaving when the team has had a bumpy end to the season should be absolutely irrelevant. Three bad results cannot even begin to undermine the three and a half most remarkable years in the club's entire history. As for Mourinho, even if some of the road has been uneven and damaging to the paintwork of the big white limousine that is Real Madrid, the fact remains he's a good driver who is set to cross the La Liga finishing line first. No small achievement.
Graham Hunter is a Barcelona-based freelance writer for ESPN.com who specializes in La Liga and the Spanish national team. You can reach him on Twitter at twitter.com/BumperGraham.