I have to improve, Van der Vaart says
New Hamburg captain Rafael van der Vaart has acknowledged his form must improve.
Hamburg have been struggling for results recently, taking only four points from their last six games, and face a battle to qualify for Europe this season.
Hamburg coach Torsten Fink this week stripped Heiko Westermann of the armband to allow the defender to concentrate on his performances, naming Van der Vaart as his replacement.
However, the Netherlands international has also played disappointingly in recent weeks and accepts he must lead by example.
"I am 30 years of age - I absolutely know when I have performed well or performed badly," Van der Vaart told kicker. "My game has to get better again, that's obvious to me. When I perform well, the chances of us being successful are higher."
Tabloid newspapers in Germany have recently reported that Van der Vaart is in a relationship with the best friend of his former wife, with some suggesting he has become distracted by events in his personal life.
"That's not right - my head feels great," he said. "I am happy. I can mute all the background noises."
Despite being 11th in the Bundesliga, Hamburg are only four points behind sixth-placed Frankfurt and very much in contention for the Europa League.
With an away game at eighth-placed Mainz approaching this weekend, Van der Vaart is determined to put an end to their run of three straight defeats.
"We need to get ready for the Mainz game now, because we can still achieve something this season," he said.
Van der Vaart has scored three goals and set up another eight in 21 appearances for Hamburg since returning to the club from Tottenham in the summer.