Dylan Stephenson broke the deadlock inside four minutes at Whitley Park, the striker's 13th goal of the season at second-string level, before the Hornets were reduced to ten men in the second-half following Kamil Conteh's red card.

Lucas De Bolle doubled the young Magpies' advantage in the closing stages with his first goal at under-23 level and despite JJ McKiernan's stoppage-time strike for the visitors, United's youngsters saw out the Group G encounter to secure maximum points.

Elliott Dickman made two changes to the side which claimed a 2-0 victory against local rivals Sunderland on Monday night as Josh Scott and Rosaire Longelo were named in the starting line-up in place of Matt Bondswell and Adam Wilson respectively. 

Newcastle's second-string had suffered a 2-0 defeat in the reverse fixture in September but were aiming to leapfrog their Hornets counterparts with a much-needed victory.

With United head coach Eddie Howe in attendance, the hosts got off to a perfect start in the 4th minute as Stephenson netted his 13th goal of the term in all competitions.

After Longelo threaded a neat pass towards Joe White, the 19-year-old - who made his first-team debut for the Magpies during a pre-season draw at Rotherham United in July - produced a delightful cross into Stephenson's path and despite seeing his initial shot blocked by Watford goalkeeper Adam Parkes, the Blyth-born forward was alert to tuck the rebound home.

United goalkeeper Dan Langley produced an impressive save to prevent Watford from swiftly equalising as the 20-year-old shot-stopper crucially blocked Freddie Moriarty's low strike with his foot, turning the ball out for a corner.

Newcastle's second-string went close to doubling their advantage as White, who was named on the bench for United's Premier League trip to Manchester United in September, saw a fierce effort from the edge of the box pushed away by Parkes.

Longelo then saw two strikes saved within the space of a minute as the 21-year-old winger, who joined the Magpies from West Ham United in 2018, saw his first attempt blocked by the body of Parkes before the Hornets goalkeeper quickly kept out a similar effort inside the penalty area.

The visitors struck the post in the closing stages of the opening half as Moriarty raced in behind the United defence, beating the offside trap, before his drilled effort struck the outside of the far post. 

In the second-half, White saw an effort flash wide of the target after the former England under-18 international advanced past James Morris on the byline before slicing his attempt wide of the target.

Stephenson went close to registering his second brace in as many matches as the striker, celebrating his 19th birthday, raced onto De Bolle's through ball before his low drive was kept out by Parkes' feet.

Watford were reduced to ten men in the closing stages as Conteh picked up his second yellow card of the evening for a late challenge on Stephenson, receiving his marching orders from referee David McNamara.

In the 83rd minute, De Bolle extended Newcastle's lead by netting his first goal for Newcastle' second-string. After White threaded a delightful through ball in behind the Hornets defence, De Bolle advanced into the box before calmly slotting the ball underneath Parkes.

United's hopes of gaining back-to-back clean sheets were dashed in the dying minutes of the cup clash as McKiernan halved the deficit as the midfielder's drilled strike from the edge of the box flew past Langley.

Newcastle United Under-23s face an away trip to Northern League Division One outfit Ashington on Tuesday, 14th December in their upcoming fixture as the young Magpies aim to reach the semi-finals of the Northumberland Senior Cup.

Newcastle United Under-23s: Dan Langley, Nathan Carlyon, Charlie Wiggett, Brad Cross, Josh Scott, Niall Brookwell, Jack Young (c), Lucas De Bolle, Rosaire Longelo (Cameron Ferguson 74), Joe White, Dylan Stephenson (Johnny Emmerson 84).

Subs not used: Reagan Thomson, Will Brown, Adam Wilson.