Defender believes Everton 'maestro' is key to Aussie's game plan...
The Werder Bremen man is wary of the threat the midfield danger can pose to opponents in Group D and believes playing in the Premier league has turned Cahill into a real threat.
Speaking at a press conference ahead of Sunday's clash between the two sides, Mertesacker said: 'Tim Cahill has enormous experience and has grown tremendously in England.
"He is one of Australia's most dangerous players and will be their maestro."
Depsite the attacking concerns, Mertesacker believes the Germans are confident of controlling his presence.
"If we can mark him tightly, it will make it hard for him to play a role," he noted.
"We will try and nip his attacks in the bud, and even maybe double mark him. But he is still dangerous and can create chances in front of goal, so it will be hard to contain him."
Despite picking up a minor neck injury in Australia's 3-1 loss to the USA, Cahill is expected to be fit to start the game against Germany.
Cahill has an impressive record for Australia, and has scored 20 goals in 40 games for his country.
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