Arsenal defender Per Mertesacker hopes manager Arsene Wenger makes a big impact in the summer market.

Mertesacker says the squad needs strengthening to be a title challenger.

"We haven't sold any players yet so we are coming from a good base at the moment, we're at a good level and no-one is leaving at the moment.

"Maybe someone will come and strengthen our squad so it's a better position than last summer when we lost two important players [Robin van Persie and Alex Song].

"It's a big year for us. We've got the World Cup at the end of it but the focus has to be on Arsenal because, of course, we want to win things and be successful this year."