A goal from Joelinton has fired Newcastle a step closer to Wembley after an action-packed League Cup semi-final first leg at Southampton.
The Brazilian, who also had an effort disallowed and was guilty of a bad miss, secured a 1-0 win for his side by burying a low cross from substitute Alexander Isak with 17 minutes to go on a breathless evening at St Mary's.
Saints thought they had levelled through Newcastle academy graduate Adam Armstrong but his bundled effort was ruled out for handball following VAR intervention.
Joelinton also had a first-half effort controversially chalked off for handball, while he wastefully blazed over with the goal gaping early in the second period.
Southampton finished a frantic encounter with 10 men after defender Duje Caleta-Car was dismissed four minutes from time.
The hosts had sufficient chances to head into the second leg level but Newcastle goalkeeper Nick Pope was in inspired form.
"Nick has been outstanding this year and every time he's needed he produces the goods for us," Newcastle manager Eddie Howe told Sky Sports.
"It was a tough game. Both teams had their moments and I'm very pleased to win the game but we know it's only halftime and there's a long way to go."
Newcastle arrived on the south coast chasing a first major domestic trophy since 1955.
Howe's men had the better of an uninspiring opening period which lacked quality and chances but contained a major talking point after a 39th-minute Joelinton effort was chalked off by referee Stuart Attwell for handball.
Joelinton somehow fired over in the 53rd minute following Almiron's neat one-two with Sean Longstaff on the right, but finally got his name on the scoresheet when he turned in a cross from Isak 20 minutes later.
Newcastle's sold-out away end was still revelling in the prospect of a first Wembley cup final since 1999 when Southampton thought they had levelled.
Armstrong scruffily finished after Samuel Edozie turned the ball across goal but the joy was cut short by VAR.
Newcastle now have a fixture-free week to prepare for the return meeting, while Saints will go to St James' Park for the second leg following an FA Cup fourth-round clash with Blackpool.