Hansi Flick’s Bayern Munich have a glamour tie to get things going, at home to Diego Simeone’s Atletico Madrid on Wednesday.

Paris: European football is reeling with stadiums largely empty and revenues down, but it is business as usual on the field for the continent’s biggest clubs this week as the Champions League group stage gets underway and Bayern Munich begin their defence of the trophy.

Hansi Flick’s all-conquering team have a glamour tie to get things going, at home to Diego Simeone’s Atletico Madrid on Wednesday.

Robert Lewandowski and Thomas Mueller both scored twice as Bayern banished their early-season blues with a thumping 4-1 win over Bundesliga minnows Arminia Bielefeld on Saturday.

It will be a fascinating contest, and as Mueller admitted after the draw was made, “the pressure is on you straight away when you are the holders.”

Before that, on Tuesday, Paris Saint-Germain return to the competition following their defeat by Bayern in last season’s final as they take on Manchester United.

They are arguably the week’s two standout ties and would be spine-tingling occasions under the lights before a full house, as would Liverpool’s trip to play Ajax in Amsterdam.

But those games will go ahead behind closed doors. After all, while UEFA is allowing clubs to open stadiums up to 30 percent of capacity, it all depends on the green light of local authorities.

The few who attended Bayern’s final win over PSG behind closed doors in Lisbon just two months ago can attest to how surreal that occasion was, and yet the quality of the football was not in question.

And so there will be a spectacle on the pitch if not in the stands, with Lionel Messi and Cristiano Ronaldo due to face each other when Barcelona and Juventus clash in Group G.

Season for a surprise?: Last season, long before the debacle of Barcelona’s 8-2 humiliation against Bayern in Lisbon, Messi had let slip that “the way we are right now I don’t think it’s enough to win the Champions League”.

They may still be nowhere near good enough, but they and the continent’s other super clubs are again aiming to stave off the four-pronged assault from the Premier League.

For all Barcelona’s current problems, they, Bayern and Real Madrid have won eight of the last 10 Champions Leagues between them, and 10 of the last 15.

It is surely only a matter of time before PSG and Manchester City get their hands on the silverware they crave more than anything, but if there is to be a surprise winner maybe this is the year.

The very biggest clubs have the strongest squads, yet they are already complaining about the punishing schedule in a season that is more condensed than ever -- the six rounds of group games are being packed into eight weeks up to early December.

Last season’s competition finished nearly three months behind schedule with a series of one-off knockout ties behind closed doors in Lisbon from the quarter-finals onwards.

Agence France-Presse