The start of Europe's domestic leagues has brought the usual excitement – new signings, new managers, new kits, new hopes. But the return of the Champions League this week will crank up the hype to a new level as the continent's powerhouses prepare to go toe to toe. Last season's all-German final saw Bayern Munich crowned European champions after a dramatic late win over Borussia Dortmund. It was also a heavy hint that the Bundesliga had taken over pole position from La Liga as Europe's top league.

But, in the Champions League era, no club have successfully defended the trophy, suggesting that Bayern Munich face an uphill battle to hold off their rivals. Over the summer, the pack of contenders grew, both in quality and quantity. Barcelona added Neymar to their star-studded squad, Real Madrid finally completed their record transfer deal for Gareth Bale, Chelsea brought Jose Mourinho back to London and Manchester City spent close to £100m to strengthen their hand.

While the drama of the knockout rounds will only arrive in February, the group stage never fails to provide a few shocks – Manchester City have been one of those victims the past two years. Inside Futbol takes a look at Groups A to H, the likely qualifiers and the intriguing storylines.

Group A: Shakhtar Donetsk, Manchester United, Bayer Leverkusen, Real Sociedad  

Despite a frustrating summer in the transfer market, Manchester United are the clear favourites to top Group A, with the firepower of Robin van Persie and Wayne Rooney likely to paper over some of the midfield limitations. Shakhtar have grown as a force in Europe and should contend for second place, but the departures of Fernandinho and Henrikh Mkhitaryan deprive the Ukrainians of true match-winning quality. Real Sociedad have thrived in the underdog role over the past 12 months and should not be overlooked. However, the Spaniards' inexperience at this level will likely count against them this year, leaving Bayer Leverkusen to sneak into the next round as the second qualifiers.

Group B: Juventus, Real Madrid, Galatasaray, FC Copenhagen
With their pursuit of Bale finally ending in success, Real Madrid can now focus on becoming champions of Europe for the tenth time. Mourinho has been replaced by Carlo Ancelotti, who knows all about this competition from his days at AC Milan and will relish the opportunity to unleash the Bale and Cristiano Ronaldo combination. They are favourites to top the group, with Juventus (another Ancelotti connection) primed to join the Spaniards in the knockout round after adding Carlos Tevez and Fernando Llorente this summer. Didier Drogba and Galatasaray will provide some intimidating atmospheres, but just do not have the quality to compete in this group. And there are likely to be some tough evenings ahead for FC Copenhagen.

Group C: PSG, Benfica, Olympiacos, Anderlecht 
Big-spending PSG stand out as the Group C powerhouses and Edinson Cavani demonstrated his love for this competition while at Napoli. Laurent Blanc's men are dark horses to reach the latter stages and much will depend on how the group gels and develops. Benfica have the added motivation of hosting the Champions League final this season and, though it is hard to imagine the Portuguese competing in that game, they look the surest bet to join PSG in the last 16. Olympiacos and Anderlecht should secure some points at home but will quickly be left adrift.

Group D: Manchester City, Bayern Munich, CSKA Moscow, Viktoria Plzen

The draw has finally taken some mercy on Manchester City, presenting a group that Manuel Pellegrini's men should navigate without too many scares. But they must learn the lessons from the past two seasons – and adding creative forces like Jesus Navas and Alvaro Negredo will help. Nonetheless, Bayern Munich are the favourites to clinch top spot (and win the competition, for that matter), even if the Pep Guardiola era has had a less than inspiring start, and the Germans will be out to cement their position as Europe's team. Viktoria Plzen's target should be damage limitation while CSKA Moscow, despite their potential to spring a surprise at home, will have to settle for Europa League action.


Group E: Schalke, Chelsea, Basel, Steaua Bucharest
Mourinho's quest for another Champions League trophy should have a gentle start, with only Schalke expected to threaten a Chelsea squad that has an abundance of creative midfield options but lacks an explosive goalscorer. Schalke will look to Klaas-Jan Huntelaar and new faces Kevin-Prince Boateng and Adam Szalai to lead their push into the last 16. The most intriguing battle may be between Basel and Steaua for third place, though the Swiss club should have the edge after a promising run in last year's Europa League (before elimination at the hands of Chelsea).

Group F: Borussia Dortmund, Arsenal, Marseille, Napoli
This promises to be the tensest group of the lot, with all four sides capable of reaching the knockout rounds. As beaten finalists last term, Dortmund are marginal favourites to outlast their rivals, leveraging last year's experience and the fact that they held onto Robert Lewandowski and secured the signatures of Henrik Mkhitaryan and Pierre Emerick-Aubameyang. Arsenal's swoop for Mesut Ozil has shifted the landscape in Group F, putting Arsene Wenger's men back in serious contention for top spot while Rafael Benitez's Napoli side have made a bright start in Serie A. Marseille, a talented team in their own right, are the outsiders, but their early season form has presented some question marks.

Group G: FC Porto, Atletico Madrid, Zenit St. Petersburg, Austria Vienna
While Austria Vienna have the unfortunate role of cannon fodder, the rest of this group should be fiercely contested. The bookmakers have installed Atletico Madrid as slight favourites to pip Porto to first place and both clubs have promising young managers. Despite the loss of Falcao, Atletico, in particular, are primed to make an impact and emerge from being the forgotten sibling to Barcelona and Real Madrid. Zenit will be no pushovers though under Luciano Spalletti – if they prosper on home turf, they might yet sneak into the last 16.

Group H: Barcelona, AC Milan, Celtic, Ajax
Barcelona have a point to prove after back-to-back semi-final exits. Meanwhile, the Bundesliga has grabbed the plaudits that were previously reserved for Barcelona and La Liga. Expect a backlash from Barcelona, led by Lionel Messi and new signing Neymar. AC Milan, still rebuilding, are expected to clinch second place, assuming Mario Balotelli keeps his cool and Kaka rediscovers some of the form from his first spell at the San Siro. But they will be pushed all the way by Ajax and Celtic. The Scots, in particular, have a solid home record in Europe and will provide a hostile atmosphere for all three games at Celtic Park.

So many big names, so many mouth-watering matches – with the return of the Champions League, the 2013/14 season truly begins this week. 

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