The former Mainz coach believes his Borussia Dortmund side were slightly lucky to scrape a win against Werder Bremen, and feels his side's sluggish performance was fitness-relatedBorussia Dortmund coach Jurgen Klopp has warned his players that they must up their game after a narrow 2-1 win over Werder Bremen in their opening Bundesliga game.
The hosts had coasted through much of the match after rocketing into an early lead through Marco Reus, but looked to have let two points slip when Theodor Gebre Selassi netted a 75th minute equaliser.
Mario Gotze rose from the bench to bag a late winner, but Klopp believes that his troops showed that they were unfit after 14 weeks without a league match.
"I was pleased with some things, but dissatisfied with others," he explained to ARD after the match. "We have had no real match for over three months, which is why I'm pleased."
Mats Hummels also felt tht his team-mates were slightly sluggish after a long break, and reminded his team-mates that they fell into bad form last season after an opening day win.
"The result was good, but I am not happy with the manner. 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."
Reus netted his first Bundesliga goal for his new club since moving to Signal Iduna Park from Borussia Monchengladbach in the summer, and the German international was delighted to have made an impact.
"This was my chance and I really wanted to score. It was really important for the team," he enthused.
"Everybody knows that you have to run a lot for Dortmund, but I like doing that."
Finally, match-winner Gotze spoke of his joy at making a vital contribution after a frustrating few months of injuries for the 20-year-old.
"That goal was so important for me. It was such a relief."
Dortmund's next Bundesliga game is a trip to Bavaria to face Nurnberg on September 1.