(Reuters) - After a week of heavy criticism, Germany coach Joachim Loew has some reassuring news for his team's supporters and an ominous warning for their next opponents -- the best is yet to come.

Speaking on the eve of Friday's World Cup quarter-final, Loew said Germany had not faced any easy teams in Brazil and that France, their next opponents, would be no different.

"We have not yet delivered our very best performance," said Loew. "We are going against a class team from France ... who have high motivations.

"France was very stable so far. Very, very good, but I think it is a game of equals and we are into it with all the self confidence that we have."

The Germans made a flying start to the tournament with a 4-0 romp in their opening match against Portugal before drawing 2-2 with Ghana then beating the United States 1-0 to top Group G.

They were then pushed to the brink by surprise package Algeria in the last 16, winning 2-1 after extra time, a performance that drew criticism back in Germany and questions about Loew's tactics.

"We haven't been constant with our performance, we started well but these teams have nothing to lose, only to win, which can sometimes make it quite difficult," he said.

"Football-wise I don't think any team has played its best yet but this is normal in a tournament.

"People said: 'Who is Algeria?' But they don't know. Or Costa Rica or others, Mexico: a great team, Chile, Colombia, all very difficult.

"It is not always possible to play your best. We can't always work out what will happen, there are mistakes."

KEY MIDFIELD DUEL

Loew has come under fire back home for his decision to put captain Philipp Lahm in midfield instead of at right back, where he has excelled for years.

He was quizzed about Lahm's position again on Thursday but gave nothing away.

"The discussion about Lahm in Germany. Where does he play? This is not new, it has been on since I was at the national team," he said.

"Such discussions don't help me and, believe me, we think about the team before every game. We are close to the players. There are decisions which are made but none that are cemented forever.

"There are many possibilities and we will see where he plays tomorrow. You will realize quite quickly."

Midfielder Toni Kroos said he was also confident Germany would produce their best against France when it mattered.

"Of course France is a top nation and we know what to expect, great players who until now have been playing well as a team," he said.

"I think we have a good chance of winning because in my eyes, (these matches) are often decided in the midfield and who dominates those duels.

"That will be our goal, we know we are good there but if we all produce our performance then we will be the better team."

Kroos conceded there was pressure to win Germany's fourth World Cup, but said it was a burden they were well used to.

"The pressure is nothing new. We have the pressure because we are good players and a top team and that's why the expectations are high, for us personally, as well as Germany," he said.

"To bring home the title. We still have a chance, we are in it, we have shown often enough that we can deal with the pressure and I hope we can continue to do this tomorrow."