Sarri’s side took the lead from the penalty spot through forward, Eden Hazard but Newcastle quickly equalized through Joselu.
DeAndre Yedlin touched the ball into his own net late on to secure all three points for the Blues.
It was three wins out of three for Chelsea under their new manager.
Sarri said that his side won Rafa Benitez’s men because his players were good and played better in the second half of the match.
The 59-year-old, however, admitted that he was shocked at Benitez’s tactics.
“I have never seen a Rafa Benitez side play with five defenders,” Sarri told Sky Sports.
“I think it is very difficult to play here for every team – not only us. We were a bit unlucky when they scored to make it 1-1.
“The match was very difficult and it was impossible to have space. We were good, better in the second half, but it was very difficult.”