Arjen Robben couldn't resist. By the time he finally got to his mobile after extinguishing the atmosphere at Old Trafford, a mate had sent a message he simply had to share: "You already know the way to Madrid". The tendency for most footballers is to play things down in weary every-game-as-it-comes language, so Robben's readiness to reveal his text reflects the new belief coursing through Bayern Munich. Nevertheless, while they may justifiably dream of Madrid, the rest of Europe will be looking no further than the semi-finals and what is arguably going to be this year's true Champions League decider: the tie between Barcelona and Inter Milan. The greatest side of the modern era – with its greatest player – against one of the greatest managers of the modern era. And the only two teams to have really taken any sort of grasp of this competition.

Which is not to denigrate Bayern or Lyon. But the Germans, certainly, were there to be taken themselves. Indeed, Manchester United had all but done so. How Alex Ferguson's side went from 4-2 up on aggregate and a thrilling 3-0 lead on the night to then go out is still astounding and slightly unforgiveable, if not unexplainable. Having exploded into the match, United then slow-punctured. In the space of 30 minutes, the game gradually and gallingly ebbed away from them. First, Ivica Olic's goal before half-time changed the psychology of the tie before Rafael Da Silva's red card changed the numbers. Wayne Rooney's forced withdrawal then removed United's impetus before Robben's volley removed their advantage. After all that, they hadn't the energy to even rouse one of their celebrated late rallies.

In such circumstances on the night, Ferguson is some way justified to speak about "luck". But over the course of the season he isn't. The point of planning, after all, is to mitigate as much as possible against the frailties of fortune. And the harsh truth is, while this Manchester United side look every bit a typical Ferguson machine when motoring, they are no longer equipped to deal with the unexpected. Recent good form – beginning with that ruthless win over Arsenal – waved away warnings there before Christmas. Too few truly top players, too little fire.

For all the talk of Cristiano Ronaldo's departure, United replaced him with Rooney but then didn't find anyone to replace Rooney. How, on Wednesday, they could have done with the energy and attacking aggression of Carlos Tevez against 10 men. Similarly, in midfield, Darren Fletcher's drive overcomes a lot of deficiencies but, as shown in recent weeks, it's the sort of high pressure that's very difficult to maintain for two matches in quick succession. That drop-off then only exposes Michael Carrick who flourishes with protection but is found out without it.

United's problems aren't as deep as many have made out and could be fixed with a few astute signings (although whether the Glazers release enough money to safeguard their investment remains to be seen). With the right midfielders, Antonio Valencia and Nani could continue to flourish. Also, the Ferguson effect could well see them still win the league. But, in the context of this quarter-final, earlier season talk by Patrice Evra that United were determined to avenge the beating administered by Barcelona appears fanciful and renders Wednesday's elimination somewhat irrelevant since it seems highly unlikely they could have lived with Pep Guardiola's side.

The manner in which Leo Messi also eliminated Arsenal has caused mass introspection in the English media, with talk of the end of an era. An era, peculiarly, only marked by two titles in five years. But, while the global bust has shrunk the big four – underlined by both the greater number of league defeats and poorer European performances – the fact there are no English sides in the last four for the first time since 2004 isn't as damning as has been deemed. Wednesday night notwithstanding, Chelsea, Manchester United and Arsenal are still arguably the third, fourth and fifth best sides in Europe.

With the gap now having been reduced between them and second-tier European sides, however, more and more games are going to be decided on – as Giovanni Trapattoni would say – the little details rather than simply greater power. Quite simply those little details, the 50-50s, went against both Manchester United in the Bayern game and Liverpool earlier in the season. A different month and things might have worked out differently. The key now, however, is that the English clubs no longer have the all-consuming power – on and off the pitch – to cast aside form and go through the motions against the rest of Europe.

Similarly, Chelsea and Arsenal were merely unlucky to draw Inter and Barcelona when they did but such are the nuances of knockout football. For all the talk of leagues rising and falling in Europe, it should be remembered both of the latter – who can now claim to be the best on the continent – have transcended their own competitions to reach that point. Jose Mourinho has overcome many of the inherent flaws in Italian football – for example, how he managed the market through the shrewd acquisitions of Wesley Sneijder and Samuel Eto'o – to construct such a disciplined but also driven side. Barcelona have played special football, meanwhile, as Real Madrid have spent special money in an otherwise financially-devastated Spanish league.

All of which points to the fact that there is no all-powerful league in Europe any more. And that makes for a much more democratic and exciting Champions League. Because, not only is this the first year since 2003 where no English sides are in the semi-finals, it's the first year since 2004 the last four are all from different countries. There was also something refreshing – for everyone except Manchester United fans – that in the last 20 minutes at Old Trafford the only two genuine world stars on the pitch played for Bayern. Why didn't United go for the resurgent Robben? With that though, some of the mystery and intrigue that marked the European Cup before it became the Champions League has returned.

Another trait of that time may well return to the competition but, contrastingly, one that actually damages the new democracy: Barca look set to become the first side since 1990 to retain it. Knockout football lies a lot more than leagues, of course – it denied Hungary '54, the Netherlands '74 and Real Madrid 2003, for example, the prizes their play deserved – and Mourinho could yet spoil the party. But, if Barça follow through with such flourish and continue to transcend football in general as well as football in Spain, a second Champions League would only confirm what their play already argues: that this is a once-a-generation side on a par with Milan of the '90s, Real of the '50s and, most of all, Ajax of the '70s. It would also give Leo Messi that key title to go with that unique talent and assure him of a place on the pedestal alongside Johan Cruyff et al. In short, a second Barça win would end an awful lot of arguments.

Mourinho, of course, wants to start a few others. Beat Barça and he can start claiming to be one of the greatest managers of all. In an interesting piece of foresight, he said as far back as the group-stage defeat at the Camp Nou how he would be ready "if we meet in the semi-finals". Seems Robben isn't the only one making plans. For this season, English clubs – and indeed Ferguson – will have to make theirs longer term.

An Open Europe

This Champions League season sees one of the most wide-ranging semi-final line-ups since the competition expanded in 1999-'00

2000 3 Spanish, 1 German

2001 2 Spanish, 1 German, 1 English

2002 2 Spanish, 1 English, 1 German

2003 3 Italian, 1 Spanish

2004 1 Spanish, 1 English, 1 French, 1 Portuguese

2005 2 English, 1 Italian, 1 Dutch

2006 2 Spanish, 1 English, 1 Italian

2007 3 English, 1 Italian

2008 3 English, 1 Spanish

2009 3 English, 1 Spanish

2010 1 Spanish, 1 Italian, 1 French, 1 German

mdelaney@tribune.ie