I would say that Chelsea's improvement is possible because of Enzo Maresca. Enzo is a great coach. Honestly, none of us thought that we would see such a great performance from Chelsea this season. I didn't even think that Chelsea would be able to come in the top four of the table. Due to Enzo's excellent match strategy, Chelsea's overall performance is now very stable. This team is performing well consistently. That is why Chelsea is now in the second place of the table.
Everything is going well for Chelsea right now because they have a good coach who also happens to have a good strategy and has also succeeded in unveiling this strategy to his player who have in turn utilized it for the club that's why you see the team playing so good. Unlike last season when Mauricio pochettino was the coach, they had to struggle to win matches because pochettino didn't engage the right strategies and at such the team couldn't succeed under him. Should they maintain this consistent wins they probably catch-up with Liverpool at the top.
Maresca innovative tactical approach and ability to develop young players has made Chelsea appear more consistent and solid, although they often lose momentum and mentality when facing big teams, in my opinion with the strategies he applies, such as flexible formations and the use of fullbacks as surprise attackers, shows a deep understanding of the modern football game he has at this time, besides that we cannot deny that the support of many quality young players owned by chelsea at this time, has made it easier for Maresca to build a better chelsea squad this season.