Germany coach Joachim Low admits there is a "major question mark" over the fitness of Bastian Schweinsteiger and Jerome Boateng ahead of Sunday's World Cup last-16 encounter with England - but is confident his side can progress.
Bayern Munich midfielder Schweinsteiger and stand-in left-back Boateng, who has just completed a move to Manchester City, sustained injuries in Wednesday's final Group D encounter against Ghana.
Schweinsteiger is struggling with a hamstring problem while Boateng is troubled by a calf strain.
And Low has conceded both are doubts to face England in Bloemfontein at the weekend.
"There is simply no way I can say at this stage whether one, or both for that matter, will be on the pitch on Sunday," said the coach. "Neither of them will train with the team today - that's for sure.
"It would be major risk, too much of a risk, to include them in training sessions.
"We will take it day by day. Let's wait and see what happens tomorrow.
"We need players who are 100 per cent fit and not 90 per cent.
"We need players who can give their all in order to survive - 90 per cent is not sufficient. They have to be fully match fit."
Low revealed both men had already received intensive treatment just to put them in with a chance of playing.
"Hats off and great compliments must be paid to our medical staff.
"Straight after the game and until late into the night and yesterday our team worked flat out to deal with Boateng's and Schweini's muscle problems.
"We can say there is a major question mark over both players."
Low insists his young side have no fear but admits there will be a certain amount of "healthy tension". This weekend's latest instalment will see a youthful Germany outfit pitted against a hugely experienced England side boasting the likes of Wayne Rooney, Steven Gerrard and Frank Lampard, players Low believes are among the best in Europe.
However, the Germany boss has faith in his players, who on Friday visited the Lion Park in Lanseria, near Johannesburg.
"I think this is a type of game which both teams will approach with a great deal of respect," he said at Germany's training base on the outskirts of Pretoria. "But while there will be respect you won't find fear in anyone's eyes, neither on the English or German side.
"No matter how important matches have been in the past, Germany have never approached these games with fear.
"There is some tension, but I would call it healthy tension.
"So great respect yes but we won't go into hiding or put our heads in the sand.
"Both teams will act with a great deal of courage, commitment and I think that, while we have a young team, we will be able to hold our own."
Looking back at past meetings between the long-time rivals, which has included key clashes in the World Cups of 1966, 1970 and 1990, as well as Euro 96, Low admits the games between the two are often spicy affairs.
"There are many chapters of the book of Anglo-German encounters on the pitch," he said. "We've had many games that were quite important. These games have always had a certain spice to them, as the Germans say, and full of sparks.
"England remain England, they can fight, they can run, they are mentally strong. They are also experienced and have class.
"So you can say it's youth versus international class, Germany v England, and we're looking forward to it."
Asked about his knowledge of English football, Low added: "We have the chance to watch English football on television in Germany, and Germany has exported its fair share of players to English shores, for example Michael Ballack, so I've often travelled to England to watch him live.
"I've always been impressed by the sheer tempo of these top-flight teams, like Liverpool, Arsenal and Chelsea.
"The English never-say-die attitude, the great fight and commitment that they always bring to the fore and, despite the high tempo, they have a superb technical level as well."
Low also downplayed suggestions that the quality of the England national team had suffered as a consequence of there being so many foreign players in the Premier League.
"I wouldn't subscribe to that 100 per cent. There are many many foreign players with prominent positions in their (Premier League) teams, but even so, the England national team's quality is beyond question," he said.
"Look at Terry, Rooney, Lampard and Gerrard... these players count among the best in Europe. England have always had players of international calibre.
"But I think not qualifying for Euro 2008 was the turning point, because Capello was hired. He injected a new sense of discipline, a clear path and a clear organisation to the team.
"They had some fantastic games during qualification, so even prior to the 2010 World Cup, England in my eyes were one of the favourites for the trophy."
There were reports of disharmony in the England camp earlier in the week but Low does not believe that will hamper the Three Lions' preparation.
He added: "I don't think this supposed discontent will have any disruptive effect.
"I think the game against Slovenia got them back on the right track and we mustn't ever underestimate these players.
"Because those players have had so many matches down the years in the Champions League, in the Premier League, they have a wealth of experience.
"So that team will not be at 100 but 110 per cent."