After decades in the doldrums, Newcastle's progress to their first League Cup final in 47 years underlined the Saudi-funded club's emergence as a serious threat to the English football establishment.

Sean Longstaff's double sealed a 2-1 win against Southampton in Tuesday's semi-final second leg at a raucous St James' Park, sending the Magpies to their first domestic final this century after a 3-1 victory on aggregate.

Manchester United are likely to be their opponents in the final at Wembley on February 26, holding a 3-0 lead over Nottingham Forest heading into Wednesday's second leg at Old Trafford.

Revitalised by the astute leadership of Eddie Howe and the financial muscle of a Saudi-backed ownership group, a club once regarded as the laughing stock of the Premier League can finally hold their heads high.

Newcastle sit third in the Premier League and look to be on the cusp of a golden era as serial trophy contenders.

"It is amazing. If you'd have said to anyone 12 months ago what was going to happen, they would have laughed," said Longstaff, a boyhood Newcastle fan.

"Since the takeover we have brought in quality players. It is really special and emotional for me what we are building here."

Their previous domestic final ended in defeat against Manchester United in the 1999 FA Cup.

That loss came in the dying embers of Newcastle's last sustained period of relevance.

Newcastle United's owners Amanda Staveley (R) looks at her husband Mehrdad Ghodoussi's phone, ahead of the English Premier League football match between Newcastle United and Fulham at St James' Park in Newcastle-upon-Tyne, north-east England on January 15, 2023. Photo: AFP

They finished second in the Premier League in 1996 and 1997, but memorably collapsed in the first of those title races when Kevin Keegan's acclaimed "entertainers" blew a 12-point lead.

It was a meltdown that epitomised their chequered history.

They have not won a major domestic trophy since the 1955 FA Cup, while their last major silverware in any competition came in the 1969 Inter-Cities Fairs Cup.

Just six years ago, Newcastle's future looked bleak despite their promotion from the second-tier Championship, which was greeted with a muted response from fans tired of their struggles during owner Mike Ashley's reign.

Ashley's reputation was so tarnished that concerns about Saudi Arabia's human rights record could not quash fans' enthusiasm for the transformative £305 million ($376 million) takeover in October 2021.

Saudi's Public Investment Fund holds an 80 percent stake in the club, while financier Amanda Staveley emerged as the public face of the ownership group.

Football obsessive

Staveley's bold declaration that Newcastle would soon be "regularly competing for major trophies" has come true more quickly than even she imagined.

At the time, Newcastle were languishing in 19th place under then manager Steve Bruce.

But, as former Newcastle striker and lifelong fan Alan Shearer said in a jubilant tweet after the takeover: "We can dare to hope again."

And in just over a year, Howe has saved Newcastle from relegation and turned Shearer's dreams into reality.

The second of Howe's two spells at Bournemouth ended with Premier League relegation in 2020, making him a gamble when he was hired in November 2021.

But the self-confessed football obsessive has seized the opportunity to resuscitate one of English football's sleeping giants.

When he is not indulging his "secret passion" for 1980s synth-pop band A-ha, the workaholic Howe spends 12-hour days at Newcastle's Darsley Park training ground.

The shrewd signings of Kieran Trippier, Bruno Guimaraes, Sven Botman and Nick Pope have added quality to Howe's squad, while the recruitment of gifted Everton forward Anthony Gordon in late January was another statement of intent.

But Howe's impact is most visible in the transformation of Brazilian forward Joelinton from an expensive flop to the heart and soul of his team.

"The easy thing is to talk about money. It's not what has got us here," Howe said.

"Team spirit and togetherness carry you a long way. We have great people in this club.

"Connecting with the culture and trying to have a small, tight-knit group is key."

A-ha have long since disappeared from the charts, but Howe is doing his best to ensure Newcastle are more than a one-hit wonder.