Dortmund currently sit 12 points behind leaders Bayern Munich in fourth place, but Klopp is hopeful his side will return from the winter break revitalised.
They warmed up for this weekend's clash against Augsburg with a 6-1 thrashing of Bundesliga 2 side MSV Duisburg in a friendly.
"Tonight one could see two teams that really put a lot of effort in offensively. We were obviously better," Klopp said.
"Defensively one or two questions still remain to be asked about four days before the beginning of the second half of the season.
"That's why it's a good thing that we can analyse the videos tomorrow and show that the defensive work can't only be done on Mondays or Fridays but has to be done properly every day."
Klopp is pleased with where his side are at ahead of the return from the winter break, but still says he has a number of decisions to make on who he will select against Augsburg.
"We have successfully completed our last friendly without too much trouble so everything is OK," he said.
"We still have three days and then we will see who will play Saturday, who leaves the best impression. After we collect these impressions we will make a decision who will be in our starting 11.
"Everybody's current form isn't the same but that's not an issue. As I said we've had players with different injuries who were training at different levels. They will all get their chance."
