Under Maresca, I've seen Chelsea's play become more solid, and overall, the Chelsea players performed well both on and off the ball. They played effectively and efficiently against a tough opponent. Just look at how they weren't provoked by PSG's play; instead, they provoked PSG, which allowed them to capitalize on their scoring opportunities.
Chelsea is now a better team all thanks to Maresca and the other coaching staff. Last two season I was comparing their strength to Manchester United, yeah the both team were not doing well 2 seasons back. But after Maresca came and Amorim came, I was expecting an improvement. So far only Chelsea has improved under Maresca which proves that he is doing his job. There is something I also noticed is that all the coaches who were under Pep Guardiola are doing well.