4) Effective new signings
One of the major reasons why Chelsea won the Premier League twice in the gap of three years - 2015 and 2017 - was because of a strong transfer window before those seasons. Players like Diego Costa, Cesc Fabregas, N'Golo Kante and Marcos Alonso came in and made a tremendous impact.
In the recent transfer window, Chelsea acquired some big names like Jorginho and Kepa Arrizabalaga, who came in to replace Real Madrid-bound goalkeeper Thibaut Courtois.
They also managed to bring in Mateo Kovacic on a season-long loan. The new players have wasted no time and have seamlessly adapted into the Chelsea system.
Jorginho, who knows Maurizio Sarri since his Napoli days, forms a vital cog both on and off the field. His ability to read the game and play decisive through balls makes him indispensable in the Sarri-ball system.
Mateo Kovacic has replicated his Inter Milan performances and has been turning many heads of late with his performances. Kepa Arrizabalaga has become a reliable figure between the posts with his work-rate and calmness.