Nkunku completed his first Chelsea hat-trick in the second half with his side’s fifth goal. Before that, Pedro Neto had registered another first, opening his Blues account with a tap-in from Mykhailo Mudryk’s square pass.
The game was also notable for the return of Ben Chilwell, on as a half-time substitute to a raucous welcome from home fans five weeks after being told by Maresca he had no future at the club.
The goals began flowing after eight minutes. Renato Veiga played a pass centrally to Felix who took a touch to evade the outstretched leg of Dean Campbell and hoisted a devilish lob forward for the run of Nkunku, the forward capitalising on his first start in four games with a shot that squeezed through the hands of Farman.
His second to make it 2-0 after 15 minutes was sublime. Neto’s back heel for Malo Gusto was cheeky, the right-back’s cross pinpoint and in at the near post stole Nkunku with an impudent flick across goal into the corner.
Chelsea by now was rampant and Felix was next to seek to get in on the act. It looked at first as though his sweetly struck free-kick had curled over the Barrow wall and bounced in off the post. Closer inspection revealed the ball had ricocheted back against the unfortunate Farman for an own goal.
Maresca’s side scored their fourth two minutes after the restart. Barrow was careless with midfield possession allowing Nkunku to nip onto a loose ball and drive forward. He fed Mudryk advancing outside him and from there, it was a simple task to find Neto for a tap-in at the far post.
Kiernan Dewsbury-Hall was denied his first Chelsea goal by a smart save from Farman, flinging himself low to his right to turn away the midfielder’s rasping drive.
At the other end Blues goalkeeper Filip Jorgensen got down well to prevent Kian Spence’s whipped free-kick from squeaking inside the post.
Barrow’s hopes of a giant killing were long extinguished, but there was almost a fairytale of a different kind when 18-year-old substitute Tyrique George had a golden chance to open his Chelsea account, skewing his shot awkwardly wide with only the goalkeeper to beat.
Nkunku finally completed his treble moments later, Farman dribbling himself into a mess and gifting the ball to the France international who rolled in Chelsea’s fifth.