PORTO ALEGRE, Brazil (AP) Germany considers itself warned.
The three-time champion has seen the challenges that Brazil and the Netherlands have already faced from opponents with lesser pedigrees in the Round of 16 at the World Cup - and the surprises from Costa Rica in the group phase.
''We don't want to have the problems that others have had - going to extra time or a shootout,'' Germany captain Philipp Lahm said Sunday, a day before facing unheralded Algeria. ''The supposedly small football countries have shown what they are capable of. We have been warned and we want to do it in 90 minutes.''
Still, neither Lahm nor Germany coach Joachim Loew would venture into naming a single player on Algeria's squad - ''because I don't want to pronounce them wrongly,'' the defender said.
''But we have definitely studied the opponent with video analysis,'' Lahm added. ''We know that this team is deservedly in the round of 16. We know what's in store for us. This is a squad that defends together, doesn't want to concede a single goal and doesn't want to lose a single duel. It's an unpleasant squad to play against.''
The 30-year-old Lahm belongs to a generation of Germany players who have shown great potential and gone deep into several tournaments but which is yet to win a major trophy.
Germany opened with an emphatic 4-0 win over Portugal then was held 2-2 by Ghana in its next match before beating the United States 1-0 to win Group G, considered the tournament's toughest.
''We can't play like we did against Ghana without much tactics and class,'' Lahm said. ''We have to play aggressively like we did against the United States. ... I think we're a better team tactically but we have to prove that on the pitch.
''We have to unleash our (strength), defend aggressively, attack aggressively and show our class,'' added Lahm, who is usually a fullback but has been used as a defensive midfielder in this tournament.
Loew's biggest lineup question could be whether to play Sami Khedira or Bastian Schweinsteiger in central midfield, with both players showing impressive form lately despite injuries.
Khedira tore up his right knee in November and recovered just in time to be selected for the squad and Schweinsteiger only recently returned from a more minor knee problem.
''Both of them are able to play from the start,'' Loew said. ''I will make a gut decision.''
In attack, Lukas Podolski is out due to a leg injury and will likely be replaced by Mario Goetze. Listed as out for two to three days, Podolski did not join the squad when it trained under a light drizzle at the Estadio Beira-Rio on Sunday.
Another option in attack is Miroslav Klose, who needs only one more goal to break a tie with former Brazil great Ronaldo for the World Cup scoring record, although the 36-year-old German will likely be on the bench.
Klose and Ronaldo each have 15 career goals on football's biggest stage.
The Porto Alegre area contains a large number of people of German ancestry, which could provide a boost in support.
''I don't know whether we will have the majority of fans, because Algeria already had 10,000 people at this stadium,'' Loew said, referring to the north African side's 4-2 win over South Korea in Porto Alegre in the group phase.
''All I know is that 4,000 tickets have been sold to German fans,'' Loew added. ''And what we have seen at Algeria's matches is that their supporters are extremely fanatic and have enormous enthusiasm. It's the first time in their history in the round of 16 and I think there will be a really good atmosphere.''
Andrew Dampf can be followed at www.twitter.com/asdampf