The struggling Saints stunned Manchester City a 2-0 to set up a clash with the high-flying Magpies, who comfortably beat Leicester 2-0 on Tuesday.
Forest edged to the semi-finals with a penalty shoot-out win against Wolves and they will host Erik ten Hag’s side, who beat Charlton to progress to the next round.
The semi-final ties will take place the weeks commencing 23 and 30 January.
Ireland goalkeeper Gavin Bazunu had a night to remember as he helped Southampton to a first League cup semi-final since 2017, following an impressive 2-0 win over Manchester City.
The 20-year-old shone against his former club, keeping a first clean sheet since October, as first-half strikes from Sekou Mara and Moussa Djenepo secured a famous home win at St Mary’s.
On his 21st appearance for the Saints, Bazunu made some key saves, including a brilliant interception to deny Erling Haaland a tap-in with 20 minutes remaining. He was commanding and quick off his line throughout the game, helped by a high starting position, and spoke about how much the shock win means to a struggling Southampton side.
“It’s massive,” Bazunu told Sky Sports after the famous win.
“It’s not just me, it’s the whole team. We have worked so hard since the manager came in, on defending the box and being really hard to beat. We need to be a hard team to play against. These results come and you have to just take them.
“The players in front of me have been absolutely amazing and worked really hard on defending the box. I think we showed that tonight. We can take a lot of positivity and take that into the game on Saturday (v Everton)."
The Saints are now one step away from a date at Wembley Stadium, with Nathan Jones’ side facing Newcastle over two legs later this month.
Meanwhile, Wolves failed to make the last four as Ireland U-21 midfielder Joe Hodge missed a penalty in their shootout defeat to Nottingham Forest, who will face Manchester United in the other semi-final.
Wolves introduced Hodge (20) for the final ten minutes and completed 73pc of his passes. Julen Lopetegui opted to leave Nathan Collins on the bench for the tie, ahead of their crucial relegation clash against West Ham on Saturday.
Forest defender Willy Boly opened the scoring in the first half, before Raul Jimienez levelled for the visitors after the break. Forest went 4-3 up in the shootout before Hodge saw his spot kick saved by Dean Hendserson, as Wolves missed out on a first semi-final since 1974.