Chelsea news: Maurizio Sarri was surprised at Rafa Benitez's tactics (Image: Getty)
The Blues left it late to finally break down a stubborn home defence, winning 2-1 after an Eden Hazard penalty and DeAndre Yedlin own goal either side of Joselu's late header.
Chelsea enjoyed vast amounts of possession, while Newcastle were happy to soak up the pressure for the majority of the tie.
But after the clash, many pundits criticised Benitez's defensive setup.
And Sarri seemed surprised that his confidant decided to sit with 11 men behind the ball for large periods of the tie, a tactic he never used when managing in Serie A.
In Italy I have never seen Rafa play with five defenders and also so compact
Maurizio Sarri
“We knew that here is a difficult game for us, especially for us, but I think for every team," he told reporters.
"Because only in the last season Chelsea lost here, Manchester United lost here, Arsenal lost here.
"So I think it is not so easy to play here against this opponent.
"The match has maybe been more difficult.
Chelsea news: Maurizio Sarri and Rafa Benitez know each other because of Napoli (Image: Getty)
"In Italy I have never seen Rafa play with five defenders and also so compact, so it was really very difficult.
"We needed to move the ball very fast and be patient.”
Chelsea may face similar scenarios this season as smaller clubs attempt to 'park the bus' against Sarri's men.
But the Italian boss is familiar with these tactics thanks to his time in Serie A.
Invalid email
We use your sign-up to provide content in ways you've consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time. Read our Privacy Policy
Chelsea star Eden Hazard netted a penalty in the second half (Image: Getty)
"I don’t know. In Italy it was usual, of course not against Inter, Rome, Juventus but if we played against the last ten in the table, it was usual," Sarri continued.
"I don’t know about here in England.
"To win here is difficult, it is very difficult for Chelsea and for every team.
"To draw with five minutes to the end for us it would have been more difficult.
"I think that this team from a character point of view is a strong team."