Joachim Loew admits he has several problems to solve after Germany failed to impress in their 2-2 draw with Cameroon as he trims his World Cup squad on Monday.
Germany host Armenia in their final warm-up match on Friday night in Mainz before flying out to Brazil the following day, but coach Loew says improvements must be made.
Germany open their World Cup campaign against Portugal in Salvador on June 16 and also face the United States and Ghana in Group G.
The German coach will reduce his squad to 23 names from 26 later on Monday having been without captain Philipp Lahm, goalkeeper Manuel Neuer and midfield general Bastian Schweinsteiger against Cameroon.
More worryingly for Loew, Arsenal midfielder Mesut Ozil was again off form in Moenchengladbach as Germany only played well in patches.
"You could see the freshness was missing, our passing game wasn't good and we made many, many mistakes," said Loew after Sunday's 2-2 draw against Cameroon.
"It's something we need to work on, our chance conversion rate is not optimal.
"We also gave away far too much ball and we left too many gaps between midfield and defence in the closing stages."
Loew singled out his chief play-maker Ozil, who was again off form having been booed off the pitch in Germany's 1-0 win over Chile in March, on the back of a dip in form and a hamstring injury with the Gunners.
"Mesut Ozil didn't have one of his better days and he needs two weeks more, but after that we will see a strong Mesut at the World Cup," said Loew.
Cameroon took a shock lead through veteran captain Samuel Eto'o on 62 minutes only for Germany to equalise four minutes later through Thomas Mueller.
German replacement Andre Schuerrle gave the hosts a 71st-minute lead before Cameroon left-wing Eric Choupo-Moting, who plies his trade in the Bundesliga for Mainz 05, popped up with the 78th-minute equaliser.
Loew has a long list of players running out of time to prove their form.
Schweinsteiger is training again after tendinitis of the knee ligament, while Neuer and Lahm are being treated in Munich for shoulder and ankle injuries respectively.
Loew played without a dedicated striker on Sunday, using attacking midfielder Mario Goetze up front as a 'False Nine' with veteran forward Miroslav Klose working his way back to fitness.
Borussia Dortmund left-back Erik Durm was impressive on his debut, while Sami Khedira produced a solid display after six months on the sidelines.
But stand-in captain Per Mertesacker admitted the Germans must raise their game before the World Cup.
"For long spells, we didn't play well," admitted the Arsenal centre-back Mertesacker.
"As long as we keep losing possession quickly, we'll have problems against any other side in the world."
With two weeks to go before their opening World Cup match, goal-scorer Mueller says their remains plenty of work to be done.
"We didn't give a good account of ourselves and we actually made life hard for ourselves," said the 24-year-old.