By ESPNSTAR.com staff
Klopp witnessed an average looking Dortmund side eke out a win over Bremen via a late goal by substitute Mario Goetze but despite the win, was displeased with the laboured display his side produced.
However, the 45-year-old was a relieved man after the win and pointed out that a lack of match fitness could have been to blame for their display.
Explaining to ARD after the game, Klopp said: "I was pleased with some things, but dissatisfied with others.
"We have had no real match for over three months, which is why I'm pleased."
Mat Hummels echoed his manager's thoughts and admitted that the team's sluggish performance was hardly befitting of title challengers but hoped this would serve as a wake up call for Dortmund.
"The result was good, but I am not happy with the manner," Hummels declared.
"The most important thing is to earn three points. Last year we had a great start and after that we had five very poor games.
"Maybe it is better to know that we still have work to do."
Having lost playmaker Shinji Kagawa to Manchester United and with the future of star striker Robert Lewandowski still uncertain, Klopp will be encouraged by the start new signing Marco Reus has made after the former Borussia Monchengladbach player scored on his debut.
The 23-year-old forward expressed his joy at having got off the mark for his new team and claimed he enjoyed playing for the team.
Reus said: "This was my chance and I really wanted to score. It was really important for the team.
"Everybody knows that you have to run a lot for Dortmund, but I like doing that."
Following a frustrating year constantly disrupted by injuries, Goetze was pleased with his fruitful comeback and said: "That goal was so important for me. It was such a relief."
Dortmund's main challengers for the Bundesliga title Bayern Munich will be in action against newly promoted Greuther Furth, a game the Bavarian side is fully expected to win.