Maresca was asked about Reds coach Arne Slot as the two prepare to lock horns at the weekend.
While Maresca’s Chelsea sit in the top four, they face a huge test as they take on the table topping Reds.
"They are doing fantastic," Maresca told reporters on Friday.
"Very good players, very good manager, very good club.
“It's already many years Liverpool are there, so they are continuing to do that and that is important for them."
"If you look at the table it is (the toughest challenge)," Slot admitted when asked about Chelsea by reporters.
"Man Utd is a top club and spent a lot, same for Chelsea in this season but they have done really well. League table, they are the toughest (so far) but it is not always about the table, we had some troubles at Wolves too, but it is a challenge, for sure.
"Very important (to be good defensively). If you want to achieve something we need to be stable defensively, we have done that so far. Now we face even better players. Chelsea, like United, have a lot of great players and we have to control that as a team but we also have to create our own chances too. Good thing is we have players who can score. An interesting game on Sunday."