The mission for Chelsea was simple: secure a win against a fourth division side, boost the confidence of the reserves and continue their period of relative happiness at Stamford Bridge. The task was quickly accomplished as Christopher Nkunku scored twice in 15 minutes to make it an easy night against Barrow.

Nkunku was the star of the show, scoring his hat-trick – and Chelsea's fifth goal – an hour later. But the hosts' attacking line also had moments of brilliance. João Félix showed imagination behind Nkunku, Mykhailo Mudryk had electrifying moments on the left and Pedro Neto scored his first goal for the club on the right. It was just too much for Barrow, although their fans remained in good spirits until the end and enjoyed the journey, even if they weren't too keen on what the destination had to offer.

Chelsea went into this game with a rare period of calm. This highly comical club suddenly looked a little more serious under Enzo Maresca, having been unbeaten since losing to Manchester City on the opening weekend of the league. As expected, they showed off their healthy supply of players in their early twenties and brought a completely new eleven for the visit of the League Two leaders, with the unpopular Ben Chilwell, 2021 Champions League winner, on the bench.

How would Barrow, who are in the third round of this competition for the first time since the 1960s, show their confidence in the opening moments? By pushing forward or with a compact defensive formation that can withstand 90 minutes? Even before the thrilling whistle blew, the joy was palpable: their travelling fans roared during the warm-up at the east corner of the Shed End, reminding everyone what this occasion meant for a club that returned to the Football League in 2020 after a 48-year absence.

But reality came quickly and with cute directness. Felix found space in a gap in midfield and slid the ball over the visitors' defense for Nkunku to hold in the box. All eyes were on the ball as it fell past Paul Farman for the first time and into the net. It had only taken eight minutes.

For Nkunku, the cups are where he has to prove himself to Maresca, the bench, his current home in the league. Here he was hyperactive in his showmanship, with sophisticated direct contact play to the goals, his second goal coming shortly after the first. It was the result of fine work down the right, Neto making way for Malo Gusto, who overlapped and sent the ball towards the near post. Nkunku came on for the reverse strike to set up the hunt for a hat-trick.

Farman, Barrow's captain, knew in advance what challenge awaited him. But he could not have foreseen the misfortune that befell him just before the half-hour mark. Félix's free-kick from central range hit the post before deflecting off Farman and into the net, an own goal. Stephen Clemence continued to direct from the flanks as his men ran hard, and the damage was limited for the rest of the half.

But the carnage continued quickly after play resumed, and any half-time wisdom from Clemence was overlooked by the wave of blue that washed over the Barrow goal. Nkunku was again a central figure, receiving a bouncing ball that the visitors failed to clear before playing on to Mykhailo Mudryk, who was advancing down the left. The Ukrainian passed to Neto, who did his part to add to the nominative determinism.

Barrow had brief moments to reward their loyal fans. Farman made a couple of good saves – a one-handed shot from Kiernan Dewsbury-Hall was the most outstanding – and Kian Spence tested Filip Jörgensen with his free-kick skills. There was a moment of pinball chaos in the 69th minute, but the ball didn't fall and no one could score a consolation goal.

Chelsea showed no signs of imploding as Maresca brought on the substitutes and gave them valuable playing time. Chilwell came on at half-time and received a big cheer from the home fans as he gleefully ran down the left in what could be a rare appearance this year.

Nkunku was responsible for his third goal himself, pressing poor Farman as he tried to make room to clear from his box, and then taking the ball from the goalkeeper to fire it into an empty net. Maresca nodded theatrically and immediately called for the striker to be substituted, who then collected his first hat-trick for the club to thunderous applause. Nkunku left the pitch, this was clearly his night.