"We go into this season with a lot of hope. The World Cup is right in front of us and this is the last stretch," Loew told a news conference.
"The Paraguay game is not a warm-up exercise but a serious test against a South American team."
Germany are top of their World Cup qualifying group on 16 points from six games, five ahead of Austria whom they play on Sept 6 before travelling to the Faroe Islands four days later.
"We have an outstanding position in our group and are on an approach flight to Brazil. In September we can take the decisive step. We want to win the group without losing a game," Loew said.
Defenders: Jerome Boateng (Bayern Munich), Benedikt Hoewedes (Schalke 04), Mats Hummels (Borussia Dortmund), Marcell Jansen (Hamburg SV), Philipp Lahm (Bayern Munich), Per Mertesacker (Arsenal), Marcel Schmelzer (Borussia Dortmund)
Midfielders: Lars Bender (Bayer Leverkusen), Sven Bender (Borussia Dortmund), Julian Draxler (Schalke 04), Ilkay Gundogan (Borussia Dortmund), Sami Khedira (Real Madrid), Thomas Mueller (Bayern Munich) Mesut Ozil (Real Madrid), Lukas Podolski (Arsenal), Marco Reus (Borussia Dortmund), Andre Schuerrle (Chelsea).
Forwards: Miroslav Klose (Lazio), Mario Gomez (Fiorentina)