Serious decisions had to be made on his arrival, notably the selling of youth product Conor Gallagher to Atletico Madrid.
The club talked to Maresca about their intentions; he has the freedom to accept players and question club decisions.
His squad is now full of players he wanted, with the exception of one case who he accepted the club’s approval for despite not being sure about.
But with Gallagher everybody was aligned.
With just a year left on the midfielder’s contract, Chelsea and Maresca found themselves between a rock and a hard place.
If he stayed he would have to renew, but they were struggling to agree on financial demands and Chelsea were never going to allow his contract to run down. The player had to depart.
Coming the other way was Joao Felix, who returned to the Blues having spent an unsuccessful loan spell there in 2023, but on much lower wages and a seven-year deal.
“I don’t do miracles,” is one of Maresca’s favourite sayings, and you can imagine him pointing that out about a player who has struggled to fulfil their potential.
The club though, were convinced he could be useful and that Maresca’s detailed work would make him better. Eventually the coach accepted the challenge.
Felix was an exception to the rule. The Chelsea model works on the basis that their potential stars – young players with huge qualities – are paid a fixed sum plus performance-related incentives.
The new ownership say they do not want to be hamstrung by high wages as the previous regime were.
It is all about trying to build a sustainable model for the long-term that allows players who impress to be rewarded with extensions and more money, as Nicolas Jackson and Cole Palmer got in their new contracts, while allowing the club to move on those who underperform, easier to do when they are on average Premier League wages.
Enzo Fernandez, for example, was signed from Benfica in January 2023 for £107m – but on a nine-and-a-half-year contract.
The deal was certainly an upgrade on what the midfielder was earning at Benfica, but still said to be nowhere near what he could have earned elsewhere.
Chelsea’s owners say the long contracts are not given with a view to trying to amortise the value of a player over a number of years, but rather to build the right model to make the club sustainable, including the shaping of a squad that can be together for years.
It does not matter how much a player costs, but they have to come with one big condition – to have the right background, character and ability to be team players.
Maresca, identified by the club to guide them for the next decade, can have any player he wants as long as they are under the age of 24 and willing to commit to the team long-term.
He wants two players for every position as a bare minimum and, with that now in place, he does not envisage signing more than two or three each transfer window.
To outsiders, one of the most impressive things Maresca has done is stabilise a squad that was seen as being hugely inflated, with talk of in excess of 45 players. The manager though has a first-team squad of 23 and that is what he has dealt with since day one.
Many clubs will have a squad of around 18 of their strongest players with the remaining numbers made of youngsters. Chelsea have added one or two more because of the schedule this season, which could see them playing 70 matches across four competitions, plus the Club World Cup.
Chelsea believe talk of an oversized squad was also exaggerated, because it included players who have suffered mid to long-term injuries, those who have been pre signed with a view to the future and others who don’t fit into Maresca’s plan and will be moved on.