The 22-year-old winger had to wait four minutes and two seconds before VAR eventually confirmed.
Three different issues arose with the goal as it potentially went out of play just before Joe Willock crossed it, Joelinton potentially fouled Gabriel and Gordon could have been adjudged to have been offside.
Nizaar Kinsella assessed the performances as Arsenal lost ground in the title race on Saturday night.
David Raya - 5
Lacked a commanding presence coming for crosses was apparent all match and he got caught underneath a cross for Newcastle's goal.
Ben White - 6
Stopped an Anthony Gordon shot early in the second half with a last-ditch challenge but saw the goal come from a cross on his side.
Gabriel - 7
Outstanding a host of physical duels including a moment of one-versus-one defending against Callum Wilson midway through the first half. Unlucky to have not earned a foul for Gordon's goal.
William Saliba - 8
Saved Arsenal on numerous occasions and his distribution was also excellent.
Takehiro Tomiyasu - 6
A good physical presence down the left but didn't contribute significantly in attack.
Declan Rice - 8
Shook off the disappointment of his midweek booing and defeat to West Ham with a dominant midfield display at St James's Park.
Jorginho - 7
In the wars with a few physical challenges and took a blow to the head from Bruno Guimaraes but fought well throughout.
Kai Havertz - 4
Lunge on Sean Longstaff was luckily deemed "reckless" rather than "dangerous" by VAR. He miraculously stayed on the pitch despite another late second-half challenge while already on a yellow card.
Bukayo Saka - 5
Saka was quiet and has found it hard to reach his usual level in recent weeks.
Eddie Nketiah - 5
Worked hard but barely laid a glove on Newcastle, despite having several shots blocked.
Gabriel Martinelli - 5
Had the best effort of the first half but shot right down Pope's throat after a good run, but was out-battled by Tino Livramento in the second half.
Oleksandr Zinchenko - 7
The best of the substitutes having shown composure with the ball and putting in some good crosses.
Fabio Vieira - 5
A very quiet cameo when Arsenal needed someone to change the game.
Leandro Trossard - 5
Similarly struggled from the bench as Newcastle sat in a low block late on.
Unused subs: Ramsdale, Kiwior, Cedric, Nelson, Elneny, Hein.