While Bayern Munich won their curtain raiser in this season' s Champions League at Greek champions Olympiacos Piraeus 3-0 (0-0) with a Thomas Mueller brace (30st goal in the Champions League) and a Mario Goetze strike, fans around the world are discussing the future of their favorite club and its protagonists.

It is not only the uncertainties surrounding Bayern coach Pep Guardiola that is keeping the fans' minds busy but also the future of Franck Ribery and Arjen Robben. Both missed Bayern' s Group F opener due to injury.

Replacing them this time was no problem. Bayern was in complete control despite failing to score in the first half and their problems with a strong Piraeus defense. Starting with a 3-4-3 system, Bayern dominated throughout and remained patient and fully deserved to wrap up their first three points by scoring three goals after half time.

"It was not an easy game as Piraeus is a strong side at home. Last year they have beaten teams like Manchester and Juventus. We had a hard time in the beginning, but managed to win in the end, which is a message too," Mueller said.

However a team like Piraeus isn' t the biggest challenge anyway for the Germans, who won their 12th Champions League opener. The coach and two key figures are the top topic right now. Some fans hope that when Guardiola decides to leave, it might at least have a positive effect on the team and club in that it unite them even more to serve up a happy end.

According to rumors, Bayern are working on the topic of a new coach with great intensity. So they won' t be helpless when the 44-year-old Spaniard announces his departure after three years, which is what most pundits are expecting. Guardiola keeps his future to himself and does not earn applause from everybody but Bayern' s officials are keeping silent because they want everybody to concentrate on the fourth consecutive German title and more importantly on the Champions League. To win the most important club competition is no less important for Guardiola himself as it would turn his era in Germany into an excellent one.

Only Bayern Munich legend Franz Beckenbauer has uttered any form of criticism. "You can' t shape a squad in accordance with his wishes and then he tells you at Christmas that he' s leaving," said the 1974 (as a player) and 1990 (as a coach) World Cup winner. "The best thing would be for Guardiola to announce that he is staying at Bayern. It would make things much easier," continued Beckenbauer sounding ironically optimistic without being able to deliver any new hard facts.

As things look like at the moment, the club' s management have accepted that Guardiola will set sail to new shores after this season, and until then, are happy about their coach' s intense ambitions to win the Champions League final in Milan in May 2016.

Former Bayern player Dietmar Hamann told the pay TV channel "sky" that Guardiola must be regarded as a special coach by Bayern. "They have been beaten badly twice in the Champions League. I don' t know if any other coach would have survived that. You can lose to Barca and Real but the naive way Bayern did was a shock to me," said Hamann.

If Guardiola leaves, his successor (and Bayern Munich) will not only have to deliver new titles but he will have to see in a new era or see out the last years of the present one. German media is already starting to talk about the end of the era for Franck Ribery (32) and Arjen Robben (31). Both had missed as well the semifinal last season against FC Barcelona (5-3 on aggregate).

In order not to be left "alone" again, Bayern' s bosses ironed out their error not to have a solution in place for the worst case and bought Brazilian Douglas Costa (Shakhtar Donetsk) and Frenchman Kingsley Coman (Juventus) to replace the aging stars down the flanks, should the two be unavailable.

"It is a general policy of the club to have quick men on the wings," said Bayern Director of Football Matthias Sammer. "We have to take care that we have a smooth transfer into the era after them," added Sammer.

How important Costa and Coman can be the duet showed in Piraeus. Over 45 percent of Bayern's attacks came over Costa and Coman delivered two assists.

The prognosis in Robben' s case is that he will be out of the game for a further three weeks. As for Ribery, Bayern CEO Karl-Heinz Rummenigge said he is expecting the player to return by the end of 2015 at the latest. The French striker has been sidelined with an ankle injury since March 2015. Both Robben and Ribery have contracts until 2017 and are obviously raring to make a comeback.

Robben answered with a broad smile when asked about the end of the era of "Robbery" (Robben and Ribery). "Until we see the post-Robben era it will hopefully still take a while. It' s always a good idea to look ahead, to recognize the time when you start to wane. But I can assure you until then it will take a while in my case," said Robben. And Ribery told reporters: "When I' m fit again, I don' t have to be afraid of any new face in our squad."