Romelu Lukaku and Thiago Silva have surprised Niguez with their quality in training.
The Spaniard joined the Blues on a season-long move from Atletico Madrid.
The 26-year old midfielder was involved in last week’s 3-0 win over Aston Villa.
Niguez names the two players who have made an impression at training in the Cobham Training Ground.
Saul said: ‘I know many of the players, plus I followed the Premier League and Chelsea a lot. I know most of the players but if I had to say a name I would say Lukaku because I haven’t followed Serie A a lot.
‘I never played against him. Against his brother yes, in the academy. Maybe I played against him as a kid in the national team but I don’t remember.
‘He and his brother are big and very strong. But I think this year in Serie A he has performed at a great level.
‘I was very surprised by Thiago Silva too. A person at 36 years, with the level he has, being a professional in the gym every day with us.
‘He works not to get injured, he is always focused, he is very intelligent tactically and understands football very well.
‘It guides you in the match. He understands football very well and has surprised me a lot for good (reasons).’