The German midfielder completed a £71million move to Stamford Bridge in September after leaving Bayer Leverkusen.
Havertz had developed into one of the most exciting players in the Bundesliga, scoring 36 goals and making 25 assists in 118 matches for Leverkusen.
But he admits he has found it ‘difficult’ adjusting to Premier League football, having failed to register a goal in the competition from his four appearances to date.
Havertz has at least already opened his account for the Blues, scoring a hat-trick in a 6-0 victory over Championship side Barnsley in the Carabao Cup.
Reflecting on his first month at Chelsea, Havertz said: ‘It was difficult for me, especially because the Premier League is a completely different league.
‘It’s more intense and I noticed that in the first few games. It has gone pretty well for me recently but I think there is also still a lot of potential upwards.
‘I want to exploit that in the next few weeks and months. The hat-trick was good for me.
‘The start was a little difficult because I only trained with the team for five or six days, then played the first game right away.
‘It was also a very big step for me to leave my family and familiar surroundings. Of course, it takes time to get it right.’
‘It’s a completely different league and the games are very exhausting. The Bundesliga isn’t worse but I noticed differences.
‘It seems to me like there aren’t any average or bad players here – everybody is at a very high level.’