Walker, who will earn his 10th cap if he plays against the Germans, says the whole squad is desperate to bounce back from the defeat.
"The mood here is always great," he said.
"We have some fantastic characters as well as players in the team, so it's always going to be buzzing.
"The defeat was a little bit of a downer, but luckily we've got Tuesday to put things right and hopefully we do.
"It's going to be a very difficult game. As a team we learned a lot on Friday against Chile, where they play the passing football, but I think it's going to be a little bit different to how (Germany) play.
"They have quality right throughout the team, but let's not underestimate us, we're a fantastic team, we've got quality throughout and I think it will be a fantastic game."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball