Berlin - Joachim Low has told his Germany stars they face "the toughest" fight for places at next year's World Cup with his defending champions hoping to secure their ticket to Russia this weekend.
The Germany squad gathered on Tuesday to prepare to face the Czech Republic in Prague on Friday before hosting Norway four days later in Stuttgart in qualifiers for Russia 2018.
With six wins out of six so far in Group C, the 2014 world champions can book their passage to next year's finals with three points in Prague, providing group rivals Northern Ireland fail to win both of their outings against San Marino and the Czechs.
For the Germans, competition for places at Russia 2018 starts now with Low saying he has 35 to 40 players in contention which will be whittled down to 23 places in his World Cup squad.
"I expect that there will be the toughest competition we have ever had," said Low, who has called up 17 members of the squad which won the Confederations Cup in July and only seven world champions.
"For as long as I have been here, the competition has never been so great," added Low who became head coach in 2006.
"Potential or talent or performances up until now are no guarantees of a free ride.
"Therefore the established players all know: they have to always go to their limits to remain in the team," he added as a warning.
The Germans unearthed the next crop of stars when Low took essentially a 'B' squad to the Confed Cup, which beat Chile in the final, after he rested all bar three of his 2014 World Cup winners.
RB Leipzig's Timo Werner could usurp Mario Gomez as Low's first-choice striker while Mesut Ozil is under pressure from Julian Draxler for the attacking midfielder berth.
Both key defender Jerome Boateng and goalkeeper captain Manuel Neuer are missing as they return from injury.
"I believe that two weeks without playing will do him good," said Low with his skipper Neuer returning from a foot fracture.
Thomas Mueller has the chance to work out his club frustrations after being left fuming on Bayern Munich's bench last weekend.
"He is an incredibly positive factor in our team, he's a leader, and I know how he always performs when he is with us," said Low of Mueller.
Low says he will be looking closely at the 'mental attitude' of his players and wants to see a clear desire to be on the plane to Russia.
"This is the big challenge, to win the World Cup and to feel the emotions of the triumph once again."