A 2-1 win over Denmark on Sunday ended a faultless group stage for Germany following wins over Portugal and the Netherlands with a quarter-final against Greece in Gdansk on Friday the next obstacle.

The 1996 champions were in fine form against Denmark dominating for long stages but Loew insisted there was more to come.

"We showed maturity in the second half, but we can still improve." Loew said.

"We lacked the killer instinct."

Strikes from Lukas Podolski and the winner from Lars Bender either side of Michael Krohn-Delhi's header for Denmark ensured Germany topped Group B undefeated, widely regarded as the toughest at the tournament.

"The match was just as tough as we thought it would be," Loew said.

"We lacked the killer instinct in the first half, which would have made it easier, and then Denmark scored. We knew we could have gone out if we had gone behind, so nerves crept in."

With Portugal leading the Netherlands 2-1 and Demark levelling it at 1-1 heading into the last 20 minutes, another goal for the Danes would have knocked Germany out of the tournament but Loew insisted he was never concerned.

"I had a plan," he said.

"Of course I had considered what would have happened if Denmark had in some way suddenly scored a goal but I never had that feeling.

"I was pretty relaxed because it doesn't get you anywhere when you panic. Bastian Schweinsteiger and Sami Khedira were always in control and I just had the feeling we would score."

Denmark defended deep for long periods and Loew said he was expecting a similar approach from Greece.

"Greece will be similar and will try to take the tempo out like Denmark."

Denmark coach Morten Olsen was proud of his side after their shock 1-0 win over the Netherlands and entertaining 3-2 loss to Portugal, paired with the Germany defeat, saw them bow out of the tournament.

"If you try to put them (Germany) under pressure, then you can get punished quickly," Olsen said.

"Being 1-1 was a good result for us because then you just need a lucky punch maybe with a set-piece, but if you gamble too much, they can hit you quickly.

"We are disappointed not to have gone through, but this team has a future."