Japan play Germany in Wolfsburg in a friendly on Saturday, the sides' first meeting since the Samurai Blue's surprising 2-1 victory at the World Cup in Qatar, which put the Germans on course for a group stage exit.
"Germany are still among the world's best, regardless of the last result" Moriyasu told reporters.
Germany have won just one of five matches since their group-stage elimination in Qatar, losing three.
The coach, who stayed on after leading Japan to the round of 16 in Qatar, said his side still needed to improve to mix it with the footballing elite.
"We have always been there in the last seven World Cups, but other countries are much stronger."
Moriyasu however said his side could still pull off another upset.
"Of course we want to defeat Germany, that's our main goal."
Moriyasu said the match would be "a good opportunity to see what we are missing".
Japan's squad includes five players who ply their trade in the Bundesliga. The coach said his side's familiarity with German football could be an advantage on Saturday.
"Many Japanese play in the Bundesliga. Every player has learned something there."
Earlier on Friday, Germany coach Hansi Flick named Ilkay Gundogan as captain, with former skipper Manuel Neuer still recovering from injury.
Flick said the Barcelona midfielder would give the struggling Germany side "new energy for us to use", alongside vice-captain Joshua Kimmich.
