The world champions have reached the last 16 where they take on Slovakia in Lille on Sunday following two victories and a draw in Group C.
In an endorsement of the team and coach Joachim Loew, Grindel told Germany’s Kicker magazine on Thursday: «Our team won the group and did not concede a goal, and the changes made against Northern Ireland (a 1-0 win) have had a positive effect.»
Grindel said he was satisfied with the results «and believe that the team is growing together every day.»
Grindel also said he could not understand criticism of Bayern Munich’s attacking player Mario Goetze. It shows «there is little credit available even though someone has great achievements.»
Goetze, who scored the winning goal for Germany in the 2014 World Cup final against Argentina, should be given more time to reach his best form, he said.