Germany face Ghana in Fortaleza on Saturday having opened their Group G campaign by trouncing Portugal 4-0 on Monday with Thomas Mueller claiming a hat-trick.

The Germans face Klinsmann's Stars and Stripes in Recife next Thursday in their final group match and Arsenal centre-back Mertesacker says his influence can still be felt.

"Klinsmann gave the younger generation the confidence which is still there now," said Mertesacker, who would win his 100th cap against Ghana.

"We're still benefitting from that time."

The 49-year-old Klinsmann, a World Cup-winner in 1990, took over the Germany reins in 2004 after the team had embarrassingly crashed out of the European Championships in the group stages without even winning a game -- the couldn't even beat Lativia.

He went on to steer Das Mannshaft to third at the 2006 World Cup before resigning to be replaced by his assistant Joachim Loew.

Under Loew, the Germans have reached at least the semi-finals of their last three tournaments, including the 2010 World Cup and two European championships.

Mertesacker said it was Klinsmann's grooming of current stars such as Bastian Schweinsteiger, Lukas Podolski and captain Philipp Lahm that helped Germany regain their position as a European powerhouse.

Germany have always had a reputation for an uncompromising, organised defence, but Klinsmann, a former striker, began the process to turn them into an attacking force.

Mertesacker added it will be "something very special" when Klinsmann's team take on Germany in Recife after the USA play Portugal in Manaus on Sunday.