Klopp: I am ready for the fight with Dortmund
Dortmund have been the biggest threat to Bayern Munich's dominance of German football in recent years and won the league twice under Klopp's stewardship in 2011 and 2012.
However, the club have endured a torrid time of it this season and a 2-0 loss at Frankfurt last Sunday left them bottom of the table with just 11 points from 13 matches.
The situation may look bleak at present, but head coach Klopp remains optimistic about reversing the team's fortunes and believes the squad will only grow closer as a result of their struggles.
"The game in Frankfurt didn't make us realise we were in a relegation battle. We have long understood what we're involved in," he said ahead of Friday's clash with Hoffenheim at Signal Iduna Park.
"At some point, we'll be able to say that we grew closer together during this time.
"Many are still hopeful and confident - that's exceptional. The club continues to grow during this time.
"I know how a relegation battle works and how a team has to think in order to get out of it.
"You don't win games 7-0 in relegation battles. You take your chances when they come to you. We have to accept mistakes.
"We've got to learn not to get down about our mistakes, instead stay calm and keep playing football.
"It's a little tough at the moment and we've got to be ready for that. I am.
"I don't need a vote of confidence, I've had it a thousand times before. The team needs it now."
Klopp could be handed a boost ahead of the Hoffenheim match after confirming that both centre-back Mats Hummels and winger Jakub Blaszczykowski have returned to training following injury lay-offs.