Havertz joined Chelsea from Bayer Leverkusen last month and has so far made four Premier League appearances and featured once in the Carabao Cup.
While Havertz has failed to find the back of the net in the Premier League, he bagged a hattrick against Barnsley in the Carabao Cup to take his tally to three goals in five games for Frank Lampard’s men.
The 21-year-old Germany international reckons the Premier League is at a higher level compared to the Bundesliga.
"It was difficult for me, especially because the Premier League is a completely different league," Havertz told Chelsea's official website.
"It's more intense and I noticed that in the first few games.
"The intensity in the duels and the runs is much higher. 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."
"The hat-trick was good for me," Havertz added.
"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."
