The 17-year-old Nwaneri, who scored his first senior goals with a brace when the Gunners romped to a 5-1 win over Bolton in the previous round, was at the heart of things again and bent in a fine shot to double Arsenal's lead after Gabriel Jesus opened the scoring with his first goal of the season.

Kai Havertz came off the bench to add a third as Arsenal extended Preston's unwanted record of having played more games in this competition than any other club, now 185, without making the last eight.

Arsenal have long known they have a potential gem on their hands – it is two years since Nwaneri became the Premier League's youngest player at the age of 15 and 181 days – and the attacking midfielder put in a performance which suggests he is ready to make a bigger contribution.

Mikel Arteta made eight changes to the Arsenal side that started Sunday's 2-2 draw with Liverpool, handing a debut to 18-year-old goalkeeper Tommy Setford.

Jurrien Timber was fit to start after being forced off with cramp at the weekend, while Oleksandr Zinchenko started to make his first appearance since August after a calf injury.

Nwaneri had the first real sight of goal but could not keep his shot down when he stretched to reach Raheem Sterling's pass near the penalty spot.

After Liam Lindsay headed over from Sam Greenwood's free-kick for Preston, Arsenal took the lead in the 24th minute.

Gabriel Martinelli floated in a deep free-kick which was headed back by Jakub Kiwior for Jesus to lash home on the volley.

Arsenal had the chance to double their lead six minutes later when Sterling picked out Mikel Merino who selflessly laid the ball off for Nwaneri, but the academy product could not get enough power in his shot.

But having fluffed that chance, Nwaneri scored from a much harder opportunity three minutes later. Played in by Jesus, the England youth international rolled away from his man before bending a shot into the top left corner of the Preston net.

Arteta made a double change at the break as Havertz and Thomas Partey came on for Merino and Timber, and Havertz got Arsenal's third within 11 minutes of the restart, arriving on cue to head Kiwior's cross beyond Freddie Woodman for his seventh of the season.

Just after the hour Woodman made a superb double save, first to keep out Jesus's low shot and then to deny Sterling on the follow-up.

From the resulting corner Stefan Thordarson inadvertently sent the ball towards his own goal but Brad Potts was there to head it to safety.

Nwaneri was desperately unlucky not to get his second in the 76th minute, finding space just inside the box and looking again for the top left corner, but this time finding the crossbar as his shot bounced to safety.

At the other end, Setford had his first real save to make moments later, clawing away a dipping shot from Jeppe Okkels. Emil Riis should have scored for the hosts six minutes from time, but poked wide from fellow substitute's Mads Frokjaer's cross.

Arsenal finished on top, but Sterling was denied by a goal-line clearance from Potts in stoppage time.

Arsenal ease past Preston into Carabao Cup quarters