The Blues returned from the international break to record a dominant 2-1 victory over Leicester City in the Premier League on Saturday afternoon.
Nicolas Jackson was teed up by Fernandez during the early stages of the game at the King Power Stadium before the Argentine doubled Chelsea's lead with 15 minutes remaining.
Although Jordan Ayew halved the deficit with a penalty five minutes into added-on time, Chelsea were worthy winners in the East Midlands.
Success for Maresca's side has ensured that Chelsea will end the weekend sitting in third position in the Premier League table.
Maresca explains Fernandez thinking
Fernandez was making his first start in the top flight since October 6, the World Cup winner delivering one of his more accomplished performances of the season.
Speaking after the match, Maresca revealed to reporters how he wants the former club-record addition to make more forward runs to help the team's efforts in the final third.
He said, as quoted by football.london: "Enzo did really well today. He is doing very well since we started. The same as I said many times for Joao Felix, the problem is it depends on the game-plan; we use different kind of players.
"Today I thought was the right game to use Enzo even if he was back from international duty [late]. I think he did very well.
"I'm trying to convince Enzo in the same way as I did last year with [Wilfred] Ndidi and Kiernan [Dewsbury-Hall] that attacking midfielders need to arrive in the box.
"The reason why he scored today was because he was inside the box and if he was outside of the box, he wouldn't have scored the goal. We are happy in the way Enzo is doing."
What next for Chelsea?
Chelsea return to Conference League action on Thursday evening when they square off against Bundesliga outfit Heidenheim in Germany.
With Fernandez having only just returned from international duty with Argentina in South America, he will realistically be rested for the midweek game.
Furthermore, Chelsea play three Premier League fixtures in the space of a week at the start of December, facing Aston Villa, Southampton and Tottenham Hotspur respectively.