Newcastle went into this second leg surrounded by nerves, despite holding that healthy 2-0 advantage in front of their own fanatical fanbase.
The unease was created by two home defeats against Bournemouth and Fulham, while Arsenal looked to be hitting their stride with a 5-1 thrashing of Premier League champions Manchester City at Emirates Stadium on Sunday.
They were also without the influential Joelinton, ruled out by the knee injury he suffered in the weekend loss against Fulham. In the end, his power and threat was not missed.
Newcastle needed a fast start, ideally accompanied by a goal, to sweep away the anxiety lingering in this thunderous environment. The dream opening duly arrived.
And it was the talisman Isak who was the inspiration, running Arsenal ragged, as he did at Emirates Stadium, in those early stages, having a crisp finish disallowed for a marginal offside then being heavily involved in Murphy's opener.
The only question was whether Newcastle could keep up the breathtaking pace and intensity, but when the tempo did die down they were able to exert a measure of control that ensured they always remained in charge of the destiny of this semi-final.
Gordon's goal was the clincher, the catalyst for a long period of celebration as Newcastle moved towards a successful finale.
And now the dream is within touching distance again for Newcastle and the supporters who crave success after that defeat against Manchester United at Wembley in 2023.
Victory against either Liverpool or Spurs at Wembley would ensure legendary status for manager Howe and his players.