Joelinton's close-range finish gave Newcastle United a 1-0 aggregate lead in their EFL Cup semi-final tie against Southampton.
The Brazilian's 73rd-minute goal settled Tuesday's first leg at St Mary's Stadium in Newcastle's favour though Southampton, who had Duje Caleta-Car sent off late on, had an equaliser disallowed.
Joelinton had a goal contentiously ruled out for handball in the first half and then missed a glorious chance shortly after the restart, but atoned when he converted Alexander Isak's cross.
VAR denied former Newcastle striker Adam Armstrong a leveller less than four minutes later, with Southampton's hopes further dented when Caleta-Car picked up a second booking.
Joe Willock wasted two good opportunities early on, hitting a wild effort over the crossbar following good work from Miguel Almiron before miscuing a volley from Kieran Trippier's cross.
Willock was also involved when Newcastle were denied an opener. Gavin Bazunu parried his shot out to Joelinton, who was contentiously penalised for handball as he fired home the rebound.
Joelinton missed a huge chance seven minutes after the restart, somehow blazing over an open goal from six yards out.
He made no mistake from his next chance, finishing into a gaping net after fantastic play from Isak down the right.
Armstrong thought he had denied his old club with a scruffy finish, only for a VAR review to rule he had handled the ball, and a frustrating outing for the hosts was capped when Caleta-Car received his marching orders for fouling Allan Saint-Maximin.
Newcastle spurned chances to further their advantage in stoppage time, but head into next week's second leg knowing a draw would be enough to book their place in an EFL Cup final for the first time since 1976.
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While Newcastle's outstanding Premier League campaign has supporters dreaming of Champions League qualification, ending a 68-year wait for a major domestic trophy is every bit as important for a success-starved fanbase.
Eddie Howe's side were good value for their victory at St Mary's, and there is now genuine hope at St James' Park that they can match the feats of Newcastle's 1955 FA Cup winners in the coming weeks.
Solid streak puts visitors on top
A crucial characteristic of Newcastle's push for a top-four Premier League finish has been their defensive solidity, and that did not desert them on Tuesday.
Newcastle have kept 16 clean sheets in all competitions this season – more than any other team in Europe's top five leagues. Goalkeeper Nick Pope was again on form, twice denying Che Adams just before Joelinton put the visitors ahead.
They have also recorded five shutouts in their last six EFL Cup games, and a similar performance at St James' next Tuesday will see them through to next month's final at Wembley Stadium.
Joelinton gets his reward
Joelinton had to bounce back from a disallowed goal and a dire miss to prove the matchwinner.
His all-round performance was excellent. He led his team-mates for expected goals (1.36) and aerial duels won (four) and was joint-top for joint-top for duels won (seven), in an all-action display.
Key Opta Facts
- Southampton have lost four of their last five home games in all competitions (W1), after losing just one of the five before that (W1 D3).
- Newcastle won an away ECL Cup game against Premier League opposition for the first time since October 2014, when they beat Manchester City 2-0.
- Caleta-Car's red card was Southampton’s first dismissal in any competition in over 12 months, since Yan Valery saw red against Swansea City in the FA Cup in January 2022.
- Joelinton has scored three goals in his last eight games in all competitions for Newcastle, as many as he managed in his previous 27.
- Pope kept his 16th clean sheet in all competitions for Newcastle, with only Leyton Orient's Lawrence Vigouroux managing more (17) among gaolkeepers for English league sides this season.
Southampton host Blackpool in the fourth round of the FA Cup on Saturday before travelling to St James' Park for the second leg of this tie.
Newcastle have a full week to prepare for that contest, having been knocked out of the FA Cup by Sheffield Wednesday.