The Slovenian opened the scoring late in the first half, rounding off a neat team move with a precise finish.

Victor Fernandez added a second less than a minute after the interval, before Vuckic all but put the outcome beyond doubt after meeting the winger’s square.

Though City improved in the following exchanges, they shipped another in the dying embers, as substitute Jamie Holmes lashed home from six yards following a corner from the left.

United enjoyed plenty of the ball early on, though they failed to really test visiting stopper Jojo Wollacott. Dan Barlaser took aim from 18 yards, but saw his effort blocked.

At the other end, the Robins’ Osagi Bascombe almost caught out ‘keeper Nathan Harker, seeing a speculative strike from range gobbled up at the second attempt.

Vuckic nearly broke the deadlock following a Barlaser corner from the left, nodding against City’s Jack Challis before powering the follow-up wide.

Midway through the half, Fernandez drew a low save from Wollacott after a burst down the left, before Harker denied midfielder Joe Morrell after the Magpies twice squandered possession in their own half.

The home side improved as the interval loomed, though, and Yasin Ben El-Mhanni saw a thunderous 20-yard free-kick rattle the crossbar before bouncing away from goal.

But, with their next attack, United took the lead.

Dan Ward picked out Fernandez’s run with a fine threaded ball, and the Spaniard’s cutback was guided home by Vuckic first-time.

The second half was just 40 seconds old when Fernandez put distance between the two sides, squeezing the ball home from a tight angle after getting the better of right-back Ashley Harper.

Newcastle’s advantage was soon even more comfortable, as Fernandez cleverly worked his way to the byline before putting the ball on a plate for Vuckic, who duly notched his fourth goal in three outings.

Vuckic perhaps ought to have completed his hat-trick with just over 20 minutes remaining, opting for power rather than placement with just Wollacott in his path, the ‘keeper doing enough to turn the ball wide.

To their credit, City improved as time wore on, and came close to a consolation on a string of occasions.

Substitute Jonny Smith lashed over the crossbar after working the ball onto his left foot, before Bascombe fired straight at Harker with just the ‘keeper to beat.

Kodi Lyons-Foster then met Cameron Pring’s dinked cross 12 yards out, but failed to get enough direction on his header.

And, right at the death, it got worse for the visitors, as Holmes added a touch of gloss to the scoreline with a thumping finish at the back post.

Newcastle United Under-23s: Nathan Harker, Jamie Sterry, Curtis Good, Stuart Findlay, Callum Williams, Jack Hunter (Lewis McNall 28 ([Jamie Holmes 65]), Dan Barlaser, Victor Fernandez, Dan Ward (Matty Longstaff 56), Yasin Ben El-Mhanni, Haris Vuckic.

Bristol City Under-23s: Jojo Wollacott, Ashley Harper, Aden Baldwin, Jack Challis, Kodi Lyons-Foster, Lloyd Kelly, Freddie Hinds (Jonny Smith 58), Joe Morrell, Cameron Pring, Osagi Bascombe (Opinin Edwards 77), Joe McNulty (James Morton 65).

Referee: Anthony Backhouse

Bookings: Newcastle United Under-23s – none; Bristol City Under-23s – Kodi Lyons-Foster (9), Jack Challis (41).