Goals from N'Golo Kante, Jorginho and Pedro sent the Blues to the top of the Premier League but for much of the first-half, Sarri's men found themselves under pressure and struggled to create chances.
"The game was more difficult than the result," Sarri told BBC's Match of the Day.
"If you see the result you think it was a very easy match but in the first half it was very difficult against physical opponents.
"In this moment we are not at the top of our potential but we had the capacity to suffer for 20 minutes in the first half.
"It depends on me and the players. The situation until now has been very difficult.
"On Monday, four players from the World Cup arrived. And then on Tuesday, another two, so it's not been easy for me at the moment. Hopefully [it will be] two months and not three."