Arsenal manager Arsene Wenger believes that Bayern Munich remain one of the favourites to win the Champions League this season but insists that there could be as many as ten sides capable of achieving European glory.

No side has ever retained the trophy since it's revamp in 1992 but Wenger has been impressed with reigning champions Bayern Munich who comfortably defeated Manchester City 3-1 in their last group game.

Wenger's own side have made an impressive start to the competition and have collected maximum points after picking up victories against Marseille and Napoli.

The long-serving Arsenal boss has suggested that his side could be genuine contenders this season but he feels it is one of the most open tournaments in recent memory.

"In the past, during the first years of the Champions League, as coaches we only expected three or four teams to potentially win. Now at least 10 teams can dream about victory in the main competition," Wenger wrote in his Eurosport column.

"Now, in October, it is literally impossible to say who is going to be the successors to Bayern. It was an impressive victory for Bayern against Manchester City. That game in particular I watched and studied and for me, Bayern are already the favourites in this competition.

"All other teams have got one goal: and that is to beat them and deny them. They are a team that can go on and win again."

Wenger also spoke of the danger Paris Saint-Germain possess after their big spending in recent seasons has seen them assemble a squad filled to the brim with world class talent.

With Galatasaray impressing under Roberto Mancini, many would have the Turkish side as a dark horse but Wenger believes it is Atletico Madrid who could spring a few surprises as the competition progresses.

"For me, Atletico Madrid can be a surprise package: they can do the same as Borussia Dortmund did last year. Even if they have lost Falcao, they have a good defence and a very good goalkeeper," added Wenger.

"They have got really good midfield players and of course they have Diego Costa - and this guy is an absolute animal. He would be able to score from anywhere.

"They are a good team with their strength spread equally across all departments. In my opinion they are a candidate to win this competition outright."