Mertersacker believes in Cech

Arsenal defender Per Mertesacker is confident Petr Cech will become a key component of a strong defensive line this season despite a rocky start to life at the Emirates.

The 33-year-old goalkeeper was criticised for his poor performance in his Premier League debut against West Ham and was blamed for both goals in the 2-0 loss.

However, Cech looked more assured in the Gunners' 2-1 win over Crystal Palace on Saturday and Mertesacker is confident he will become a vital part of Arsenal's defence.

"Petr is very experienced. You can feel that, he has lots of things to say and in the dressing room he gives us a great lift," he told Sky Sports.

"Even when we lose a game, he has some great ideas on and off the pitch. He is experienced enough to think about what went wrong, you don't have to tell him.

"My feeling is he comes back even stronger, so there is no doubt he will be a great addition for us. Even when you are experienced, sometimes mistakes happen.

"The interaction between the goalkeeper and the back four has to be top to compete in the Premier League. Sometimes it takes longer than you think.

"Petr came and had that understanding from the start, we both communicate well and understand each other as someone who has to talk and is really responsible.

"We match our ambitions on the pitch and so it is great to communicate with him," the Germany international concluded.