Lavia has made six starts and three substitute outings so far this season after missing most of the 2023/24 campaign through injury.

His performances in the heart of Maresca's midfield have created a lot of excitement among supporters and showed why Manchester City, tonight's opponents Southampton and now the Blues have put so much faith in the Belgian despite his young age.

Maresca was Lavia's head coach during Manchester City Under-23's Premier League 2 title win back in 2021 so he knows all about the midfielder's prodigious talent.

And he told journalists: ‘Romeo is doing very well with us but because I know him well, he can do much better. I am very happy with Romeo but he can do better because he is a top player. The only thing is he is 20 so has to improve many things. So we are very happy with him, he is doing fantastic but he can improve many things.’

When the topic of 'trusting' Lavia despite his young age came up, Maresca added: ‘I trust him for sure but Romeo didn’t play against Leicester so two games ago he was on the bench, but because he’s on the bench, that doesn’t mean we’re not happy and he’s not doing well. It’s the game plan that’s changed for the game. We are completely happy with Romeo.’

One of the most prominent ways Maresca has looked to adapt his plan based on the way the opposition play is in the use of his full-backs.

In some games this season we have seen Marc Cucurella on the left and Malo Gusto on the right play in a defensive midfield role when we have the ball, while in others they have featured wide on the touchline and also in an advanced No.10-like position as Maresca looks to create an overload in the midfield and attacking third.

And on Sunday during our 3-0 victory over Aston Villa, with Reece James out injured and Malo Gusto returning to full fitness, Moises Caicedo played in the right-back position out of possession but on the ball, the Ecuadorian moved into the centre of midfield where we are accustomed to seeing him operate.

Maresca said: ‘We try to change the plan. It depends on what the other team do on and off the ball while maintaining our principles, no matter if it’s Carabao Cup, the Conference League or the Premier League.

‘We change players and structure, but in the end, the identity has been there. When we move players like against Aston Villa, we think for that game it’s a good option and until now it’s happened many times and hopefully it happens again in the future.

‘One thing I can say is since we started, Malo Gusto, who was playing inside from right-back, was probably the first one who helped us a lot in terms of that process because he gives us that option, because Romeo was injured and Moi was playing a different position. But we always thought Moi in that position, inside like against Aston Villa, could be a fantastic option for us.’

Maresca has more than seven years experience as a full-time coach, having been on the staff at Serie B club Ascoli, worked under Pep Guardiola twice at Manchester City, with Manuel Pellegrini at West Ham United and had a brief stint as head coach of Parma before he became Leicester City boss in the summer of 2023.

The Italian's first season in charge of the Foxes saw him win the Championship title and attract the interest of Chelsea.

Third in the Premier League, level on points with second-place Arsenal, and top of the Conference League table, Maresca's start to life at Stamford Bridge has been positive. But Maresca was asked if he doubted himself at all or was worried before taking the job due to his 'lack of experience' at the top level.

‘Doubt myself? No, for sure [I didn’t],' Maresca said. 'Every Premier League manager is the same. Eddie Howe when he started, did he have experience? No. Pep at Barcelona? No. Mikel at Arsenal? No. When you started as a journalist, did you have experience? No. We all are in the same situation.

‘When you start you don’t have experience and you cannot go to the supermarket to buy experience. For all of us in different jobs it is the same.

‘In terms of doubting myself, no. But when I finish a game and you ask me if I’m worried about this or that, I’m always worried because I am always trying to do the right things until the end. But that doesn’t mean I don’t believe in what I do.’

When Maresca's Leicester City won the Championship title they were joined in promotion by Ipswich Town and Southampton, who Chelsea face tonight at St Mary's Stadium at 7.30pm GMT.

The Saints have had a tough start to the season, picking up just five points from a possible 39, but Maresca insists that is not an accurate reflection of the job Russell Martin is doing or the way his team are playing.

Maresca said: ‘I really think Russell Martin has been doing fantastic since last season, not only for promotion but the way they got promoted. This year they have struggled in terms of results but in terms of performance, they probably deserved more points.

‘The first thing I said to the players in the changing room after the Aston Villa game was not ‘congratulations’ or ‘well done guys’, it was ‘prepare for Wednesday because it is the toughest game of the season for us and we need to be ready’. Then I said congratulations and those kind of things but the first thing after Villa was ‘be ready for a tough game’ because I had already been watching Southampton and in most of the games they deserved something more.’