The irony will surely not be lost on Mikel Arteta. On a night when his side were hoping to put one foot in the Carabao Cup final, it was Alexander Isak– a striker that the Arsenal manager has long coveted – who did the damage as Newcastle secured a famous victory.

It was no less than Eddie Howe’s side deserved as they bid to reach the final once again after the heartache of losing to Manchester United at Wembley in 2023. Goals either side of half-time from Isak – his 10th in his last nine appearances – and Anthony Gordon ensured they will go into next month’s second leg at St James’ Park with a healthy advantage. While Arsenal had 23 chances in total, only three were on target and there was no need for the referee John Brooks to explain any video assistant referee decisions to the crowd in an initiative being trialled in the semi-finals as the hosts struggled to respond after falling behind. They left the pitch to a smattering of boos from those supporters who remained at the end and Arsenal’s hopes of winning a second major trophy since Arteta took charge now look distant. But Newcastle’s fans – who serenaded Howe and his players after the final whistle – can almost start to plan another trip to London in March.

Related: Arsenal v Newcastle United: Carabao Cup semi-final, first leg – live

A reflection of how much this competition has moved up the priority lists of both clubs could be seen in the strength of both starting XIs. But while Arsenal’s situation was dictated by the lack of options in attack after the muscle injury sustained by the teenager Ethan Nwaneri against Brighton meant he joined Bukayo Saka on the sidelines, Arteta may come to regret having placed so much importance on this competition given their aspirations to win bigger trophies in the future. Having somehow failed to find a way past an inspired Martin Dubravka – who appeared to wave an emotional goodbye to the Newcastle supporters at the end amid reports he is set to join Saudi side Al-Shabab – when Jurriën Timber and Gabriel Martinelli spurned golden opportunities in the first half, a poor header from Kai Havertz that came off his shoulder when the score was 2-0 summed up a disappointing evening for the home side.

Newcastle’s run of five successive Premier League victories has coincided with a reconfiguration of their midfield to accommodate Sandro Tonali and Bruno Guimarães. But with the Brazilian suspended, Howe turned to Joe Willock – another Arsenal academy graduate who was allowed to leave north London by Arteta in 2021 and put in a real shift before making way with 25 minutes to play.

With his side in such good form, Howe acknowledged that this competition may be their best chance of ending the quest for a major domestic trophy that stretches back to their FA Cup win in 1955. However, they were facing an Arsenal side that are desperate to shed their tag as nearly men and tore out of the blocks. Timber should have made more of Declan Rice’s corner that sailed over Dubravka’s head early on but he could not direct the header on target. Martinelli then struck a post when he was played through brilliantly by Martin Ødegaard, before Newcastle somehow scrambled another corner away when Dubravka flapped at the ball and completely missed it.

But the 6,000 travelling supporters in the Clock End could celebrate when the Newcastle goalkeeper pumped a free-kick forward and it was flicked on by Sven Botman. Jacob Murphy’s touch took the ball perfectly into the path of Isak and from that moment there was no doubting the result as his finish into the roof of the net left David Raya with no chance. Arsenal balked at paying the Sweden striker’s release clause when he was at Real Sociedad before he eventually joined Newcastle for £63m, with Chelsea reportedly quoted £150m to buy him in the summer. How Arteta must wish they had followed up that interest now.

There was more concern for Arsenal when Leandro Trossard hobbled down the tunnel at half-time after clashing with Gordon. It was a surprise when the Belgium forward re-emerged but his side soon found themselves two goals down after more brilliance from Isak. A clever one-two with Murphy took him inside the area and his shot was parried by Raya straight into the path of Gordon, who tapped into the empty net to the delight of the fans behind the goal.

Arsenal were living on the edge and only just managed to scramble away a dangerous cross from Tonali. Arteta’s head was in his hands when Havertz somehow contrived to make contact with his shoulder with the goal gaping after the ball had looped up from Trossard’s cross. The Arsenal manager turned to Gabriel Jesus – the hat-trick hero from their quarter-final win over Crystal Palace – off the bench but his first act was to head over another Rice corner when it seemed easier to score.

Howe sacrificed Murphy and Isak as Newcastle attempted to shut up shop, with Joelinton blocking a shot from Jorginho before Martinelli was well off target with the follow up. But that and the Italy midfielder’s late effort that cleared Dubravka’s bar was as close as Arsenal came to finding a way back into this tie to leave Newcastle on the verge of another final appearance and their longsuffering supporters in dreamland.