Sun may well be setting on Barcelona

Hello Bayern, goodbye Barça. There’s a sense a torch is being passed on the continent, following the Bundesliga champions’ 4-0 evisceration of La Liga’s champions-elect in Munich last week.

The cliff-face Barça must negotiate in the return leg at the Camp Nou tonight looks unscaleable. Xavi Hernández, Barcelona's field marshal, admits his side will need a "miracle" to prevail. Divine intervention is unlikely given the ropey condition of his team-mate's right hamstring – Leo Messi was a study in hands-on-hips frustration in the first leg, running 4.5km less than Xavi during it.

Bayern Munich exposed old failings in Barcelona's team – vulnerability to set pieces; the ease with which they were muscled off the ball; and, because their full-backs play as virtual wingers and they took the field with a makeshift central defence, they were easily undone by quick counter-attacks.

And of course, a vulnerability to what the Spanish press call " Messidependencia ".

Possible demise
Is the sun setting on Barça's great team? There have been signs of a possible demise. For all of Messi's goals, Barcelona registered their worst defensive record since 1962 in February. Real Madrid beat them four times in the last 12 months.

There were wobbles in Europe against Celtic, Milan and Paris Saint-Germain.

“Barcelona have lost their aura,” said Uli Hoeness, Bayern Munich’s president, before the first leg clash, alluding to a shift in the balance of power from Catalonia to Bavaria.

It has been a long Catalan reign by modern standards. Barça set a record by playing in its sixth European Cup semi-final in a row this season. It is an extraordinary accomplishment in an era in which no team has managed to retain the Champions League since its format changed in 1992, the year Pep Guardiola, creator of the Messi & Co team, won his European Cup medal with Barça.

Sleeping tablets
Guardiola's decision to end his footballing sabbatical and sign as manager for Bayern Munich is telling – both for the reasons he chose to leave Barcelona and for the choice to take up with "Bayern over the noise of England", as El País put it.

When Guardiola left the Camp Nou last May, he cited exhaustion, having been reduced to taking sleeping tablets.

His tight control over players was slackening. He discarded troublesome stars in the early days like Deco, Ronaldinho, Samuel Eto’o and Zlatan Ibrahimovic (who called him a coward in a dressing-room outburst), but he struggled to crack the whip with errant, favourite sons in his last season.

Players were dropped, such as Alves, who returned to Barcelona late in January 2012 after the Christmas holidays, and Gerard Piqué, who was tailed by Metodo 3, a detective agency, hired by the club to monitor his nightlife with pop star girlfriend Shakira. Guardiola was conflicted. “I want to tell a player off and then hug him immediately after,” he said.

Bayern Munich, one of the aristocrats of European football, represents an enthralling prospect for him, with a formidable squad that will add 20-year-old playmaker Mario Götze, filched from rivals Borussia Dortmund, to its roster.

According to Dortmund boss Jurgen Klopp, the chance to play under Guardiola was the reason Götze left for €37 million, a record between two Bundesliga clubs.

Guardiola may deploy Götze as a “false nine”, the position he converted Messi to in 2008, which resulted in a huge spike in the Argentine’s scoring, from 16 in Frank Rijkaard’s last season in charge at Barça to 38 in Guardiola’s first year at the helm and 73 in his last.

Bayern Munich's playing style – pressing defence; quick circulation of the ball; and two wingers, Franck Ribery and Arjen Robben, behind a striker - was put in place by Louis van Gaal, who Guardiola admires, and one of the Dutch architects of Barça's tiki-taka template.

Underage system
Bayern, like Barça with their vaunted youth academy at La Masia, have stocked their team with products from their underage system, including Thomas Müller, Bastian Schweinsteiger, the injured pair Toni Kroos and Holger Badstuber, Diego Contento and captain Philipp Lahm.

Guardiola liked the look of the club’s infrastructure, too; much of it resembled Barcelona’s. Both clubs are member-owned, 82 per cent by fans in the case of Bayern Munich (as are Real Madrid and Borussia Dortmund). The clubs are run democratically. Presidents are accountable to members, in contrast to the plutocrats who have gobbled up England’s grand old football institutions over the last decade.

Bayern Munich are in rude financial health, with revenues twice that of Borussia Dortmund, its closest domestic rival (but still €120 million shy of Barcelona’s, according to figures from January’s annual Deloitte Money League).

How long will it take for Barcelona to rejuvenate for further tilts in Europe? They still have a young team; Xavi, playing in his 15th season with Barcelona, was its only outfield player over 30 years of age in the first leg, andaccording to reports they have as lodged a€10 million deposit with Santos for Neymar.

Bayern Munich lost 4-0 at the Camp Nou in the 2009 Champions League quarter-final, during Guardiola's march towards his first Champions League title as a manager. Tonight, the Germans will undoubtedly progress. Will Guardiola, an interested onlooker, oversee the decisive years in the clubs' rivalry?

Richard Fitzpatrick is the author of 'El Clásico: Barcelona v Real Madrid, Football's Greatest Rivalry', published by Bloomsbury.