TodayGroup BNetherlands     vs    Denmark    17:00   SS3Germany     vs     Portugal    20:00  SS3GDANSK - Germany know they must curb Portugal forward Cristiano Ronaldo’s dizzying runs down the left in their Euro 2012 Group B opener on Saturday but their shaky defence has yet to show it is up to the task.Coach Joachim Loew has a wealth of midfield talent but far fewer options in defence with a final decision on his centre backs still pending as Germany bid for a fourth European crown in a tough group that also includes Netherlands and Denmark.While Holger Badstuber looks set to start at the heart of the German backline, speculation over his partner continues.Fellow Bayern Munich defender Jerome Boateng is likely to switch to the right, a position he is uncomfortable with, to make way for central defender Per Mertesacker. Lars Bender could also an option at right back, Loew said on Thursday.The experienced Mertesacker, however, has hardly played since an ankle injury in February and looked completely out of place in the 5-3 friendly defeat by Switzerland in late May.Captain Philipp Lahm will shift from his usual slot on the right to left back which is not his preferred position."We will need to talk a lot on the pitch and to support each other,” Mertesacker said. "I am experienced in understanding what the team needs.”"We have angered him (Ronaldo) a few times in the past and we must do it again. What we should not do is give him too many one-on-one situations.”STOP RONALDOThe defence will rely on holding midfielders Sami Khedira and Bastian Schweinsteiger to get early tackles in on Ronaldo, though ‘Schweini’ is far from his best after nursing a nagging thigh problem for two weeks in a season sprinkled with injuries.For Portugal, the key to success against Germany will be how Ronaldo plays his part in his team’s collective effort.The forward has said Portugal’s aim is to win the tournament after coming agonisingly close as hosts in 2004 when they were upset by outsiders Greece in the Lisbon final.The Portuguese, however, have not beenn impressive in their last two friendlies, drawing 0-0 against lowly Macedonia and losing 3-1 to Turkey on June 2."We want to go as far as possible, and our first objective is the quarter-finals, that is what is set out at the moment,” said Portugal coach Paulo Bento.