Chelsea defender Fikayo Tomori says his first season in the Premier League has been a mental challenge.

It is the varying challenges that provide the toughest scrutiny for defenders in the top flight and which require the utmost levels of focus and concentration.

"It is tough because you come up against different strikers and different systems that teams use," Tomori told chelseafc.com.

"Some teams might play two strikers up top, some may play one and then you have teams like Liverpool - we all know how Roberto Firmino likes to drop in, with Mo Salah and Sadio Mane running in behind so you need to have that concentration all the time.

"It's about always being aware of what's going on around you, communicating with team-mates around you to help them and make your job easier.

"Everybody knows that if you make a mistake in the Premier League, you're likely to get punished so being able to stay focused and making sure you do everything at 100 per cent is another part that you have to grasp quickly."