Targeting a place in the competition's Round of 32 stage for the first time since 2018/19, Kyran Thompson's composed finish fired United's youngsters into a half-time lead at the AESSEAL New York Stadium.

Newcastle's second-string produced a resolute defensive display against the League Two outfit, who won the competition in 2022, to record a fifth consecutive win in all competitions.

Robbie Stockdale made five changes from Friday's Premier League Cup win against Peterborough United as Mason Miley, Thompson, Miodrag Pivaš, Dylan Charlton and Matheos Ferreira - the latter receiving a first international call-up for Brazil Under-20s - all featured in the starting XI.

Magpies goalkeeper Roman Dowell, a representative of England at Under-18 level, produced a key stop to prevent Kian Spence from handing the Millers an early lead as the 16-year-old got down quickly to hold the Rotherham midfielder's fierce drive from the edge of the penalty area.

Vakhtang Salia aimed to score a sixth competitive goal of the season at Under-21 level in spectacular fashion as the Georgian striker's audacious lob from the halfway line landed comfortably into the gloves of Rotherham goalkeeper Ted Cann.

Miodrag Pivaš, who made his first senior start for the Magpies during August's pre-season friendly away at Valencia, went close to firing the visitors ahead as the Serbian defender connected with Thompson's teasing free-kick into the box but saw a firm header fly wide of the left-hand post.

Dowell carried out a further save shortly after as the Boldon-born youngster, who became the youngest English goalkeeper to feature in the UEFA Youth League last term, beat away Klaidi Lolos' powerful strike at goal following a dangerous attack from the hosts.

In the 34th minute, Newcastle took the lead as Thompson completed a neat counter-attack, the 17-year-old forward's fourth goal in as many starts at Under-21 level.

After Alfie Seldon collected the ball from distance, the left winger fired a neat pass into Salia's path before the latter set Thompson through on goal before the London-born youngster cooly lifted the ball over the incoming Cann.

Thompson was unable to double his and United's tally before the break as the England Under-18 international, who was named on the bench for the Magpies' Premier League victory against Hull City in September, got onto the end of Dylan Charlton's inviting cross but steered his volley straight into the hands of Cann.

Newcastle went in search of a second goal in the second half as Ferreira's floated cross found Charlton at the back post but the Gateshead-born full-back's attempted shot flew across the face of goal, with Sonny Aljofree clearing the ball from the box.

In front of 805 spectators, including 72 away fans, Thompson went close to scoring in the closing stages as the promising teenager's bending free-kick was pushed out for a corner by Cann before his stinging drive minutes later forced the Millers goalkeeper into punching the ball away from goal.

Despite five minutes of stoppage time, Newcastle dug deep to record a second win in this season's competition and will top their respective group should Bradford City lose by four or more goals against York City in next week's Northern Group C fixture.

Newcastle United Under-21s: Roman Dowell, Scott Bailey (c), Dylan Charlton, Kyran Thompson (Guy Bloomer 90), Vakhtang Salia (Michael Mills 73), Logan Watts, Henry Johnson, Matheos Ferreira (Luke Craggs 73), Mason Miley (Jayden Kouossu 73), Alfie Seldon (Kyle Fitzgerald 73).

Subs not used: George Mair, Park Seung-soo.