German international defender Per Mertesacker extended his contract on Sunday with Bundesliga giants Werder Bremen.

The 23-year-old, capped 47 times, extended his contract from 2010 to 2012 as he believes that Werder can genuinely challenge for the title, after finishing second last season, 10 points adrift of champions Bayern Munich.

"I am convinced that we are going to be serious challengers for the title, we are strong in all sectors of the team," said Mertesacker, who joined Werder from Hannover in 2006.

Mertesacker, a member of the German side that reached the 2006 FIFA World Cup Germany™ semi-finals where they lost to eventual champions Italy, is presently on UEFA EURO 2008 duty with the Germans and preparing for Wednesday's semi-final with Turkey.