Thomas Tuchel has said his initial doubt over the offer of an 18-month contract by Chelsea was quickly overtaken by the desire to author his own destiny, mindful that the length of any deal was most likely no indicator of security. The reputation of Roman Abramovich for ruthless managerial sackings was burnished on Monday when the owner replaced Frank Lampard with Tuchel after a run of five defeats in eight Premier League games. Previously, Chelsea had been third, two points off the top. Tuchel, whose first match in charge ended in a 0-0 home draw with Wolves on Wednesday and entertains Burnley at Stamford Bridge on Sunday, has entered the job with his eyes wide open. He has resolved to be himself and not worry about the problems or risks – such as that only José Mourinho has lasted longer than two seasons as manager during Abramovich’s 18-year stewardship. “At first, it was a concern – a little bit like: ‘Oh, why 18 months?’” Tuchel said. “After one minute, I thought: ‘What does it change if they gave me four and a half years and they sack me anyway? If they are not happy, they will sack me anyway.’ “I decided not to worry about that too much and to go to do it, to be brave enough to take this adventure. It’s my character to believe more in the chances than in the risks.” Tuchel has fallen out with members of the hierarchy at his previous two clubs, Paris Saint-Germain and Borussia Dortmund, and he would be wise to tread carefully at Chelsea. But even though he has learned from the experiences, he said he can never play insider games. “I am as far away from being a politician as being a maths teacher, because I was horrible at maths at school. I am a football coach and I have absolutely the feeling, 100%, that Chelsea signed me as a football coach.” Tuchel knows he must win trophies but is clear it is what he expects of himself anyway, along with improving players such as Kai Havertz, who has struggled since his £72m move from Bayer Leverkusen. “We will push him and he seems to be like a guy who needs to be pushed,” Tuchel said. “We will not stop doing it. For him, this league is perfect because he cannot rest. He has so much potential that he needs to be challenged, physically also. “It is not enough for him to rely on his endless talent. For me, the question is does he have this [mimes a snarl]. Can he show his teeth when it gets tough?”