Khedira prepared for Germany's tricky clash with Mexico

Germany midfielder Sami Khedira is expecting a difficult test from Mexico when the World Cup holders begin the defence of their title on Sunday.

Khedira is one of a number of players in Joachim Low's squad that tasted victory in Brazil four years ago and will play a key part in Germany's quest to become only the third nation to retain their the crown.

Mexico, regulars in the competition and a side expected to advance to the knock-out stages, present Die Mannschaft with their first hurdle and Khedira is wary of the challenge they present.

Germany defeated Mexico 4-1 in the Confederations Cup last year in a competition Low's side went on to win, but Khedira told the official website of the German Football Association (DFB): "They play great football, they're an aggressive team; the word "tricky" sums it up.

"We definitely shouldn't underestimate them even if we did beat them convincingly in the Confederations Cup last year.

"We're taking this match very, very seriously - especially since it's our first game at the World Cup. We don't know exactly where we stand and we don't know exactly how well they'll start at the World Cup."

Mexico have been knocked out in the round of 16 in each of the last six World Cup tournaments and will look to experienced striker Javier Hernandez to lead them in Russia.

"I played with Chicharito at Real Madrid. He's a player who never gives up, which makes him a symbol for the entire Mexican team," Khedira added. 

"He's always playing hard and he's technically brilliant. He may look harmless, but he has a huge amount of talent.

"He's aggressive in the challenges and never stops running. Chicharito is definitely the embodiment of a Mexican player."

While Germany will be confident of progressing deep into the tournament, Khedira knows they may find opposing teams encouraged by the challenge of a clash with the defending champions.

"We have a lot of quality. The danger is that at times you can start thinking: 'We are World Champions, we are Confederations Cup winners, we have the quality, we are good footballers.' But the deciding factor will be playing as a team and being hungry for more success," Khedira explained.

"These factors decide games and in the end tournaments – we can't rely on our quality.

"The lads who we're playing against will run that extra mile against us, the World Cup holders, they'll be more aggressive and more motivated. If we let up in any way we'll get beaten, but, as I said, we have a team full of champions. We need to give even more than in 2014 in order to win it again."