"It's just about striking up a better understanding at the back," he said. "We all come from different clubs with different ways of playing, but we know that we will get a month before the World Cup to get it right, so we've got that time.
"Of course we made some mistakes, but we dominated the game and created plenty of chances and fully deserved the win."
He said: "They had two chances and all of a sudden we were 2-0 down, but ok, we've turned it around to win 5-3, which is not really the best of results, but it's still nice. In terms of the points, qualifying has been great, but maybe not in terms of the goals conceded."
While doubts persist about the state of the Germany defence, there is no such concern when it comes to the strength of their attack.
A present for mum?
Andre Schurrle netted a hat-trick with Mario Gotze and Mesut Ozil all on target, proving they can still turn it on even without a recognised striker.
"We've seen once again how strong we are going forwards," said Chelsea midfielder Schurrle. "Everybody struggles against us. In the second half, we upped the tempo and they had problems and we fully deserved to beat them."
As a result, Schurrle got to keep the ball for the first time, leaving him only unsure about what to do with it.
"This is my first hat-trick so I've got to see," he said. "Maybe I'll give it to my mum."