The game flared up as early as the third minute when Levi Colwill reacted to a late challenge from James McClean. The pair grabbed each other, sparking a melee which included Wrexham coach Phil Parkinson trying to separate the two players.
Chelsea, who named Colwill, Noni Madueke and Romeo Lavia in their starting lineup, dominated the ball and operated with Reece James utilised as an inverted full-back when in possession -- a key trait of Maresca's time at Leicester City, where he won the Championship last season.
Nkunku fired Chelsea in front after Tyrique George's shot was blocked by Marc Guiu in the box. The loose ball fell perfectly for Nkunku, who thrashed a shot past Arthur Okonkwo and into the bottom corner.
