Terry Devlin's first international goal kept Northern Ireland top of their Nations League group as a 1-0 win over Ukraine set up a promotion decider away to Hungary on Tuesday.
The 23-year-old Devlin has been in the goals for Portsmouth this term with four, and opened his Northern Ireland account with a fine strike in the 68th minute as he left Ukraine goalkeeper Anatoliy Trubin flat-footed with a shot from distance.
Pierce Charles then made a superb save to deny Danylo Sikan at the death and preserve Northern Ireland's fifth straight clean sheet - the first time they have achieved that since 2017 - and ensure they remain the only side in the competition yet to concede.
The three points put Northern Ireland back on top of Group B2 after Hungary's 2-0 win over Georgia earlier in the afternoon, and ruled Ukraine out of contention as they lost three straight matches for the first time in six years.
A draw in Budapest would be enough to elevate Michael O'Neill's young side to League A, while even in defeat they would face a play-off in March, and they have also earned a pot two place in next month's Euro 2028 draw.
However, O'Neill will need to watch Tuesday's match from the stands as he joined Jamie Donley - who had a first-half strike ruled out for offside - in earning a late yellow card that results in a suspension.
The match burst into life in the 23rd minute. Justin Devenny slipped the ball to Isaac Price, whose left-footed strike hit teammate Ethan Galbraith and ballooned up, falling for Donley to finish - but VAR intervened with the Luton man fractionally offside.
Moments later, Devlin's low cross found Donley at the near post but Trubin blocked his shot and then the follow-up from Shea Charles.
It was an excellent double save from the Benfica goalkeeper, who was on the bench last month when Dmytro Riznyk let in all three of Northern Ireland's shots on target in the reverse fixture.
Ukraine immediately threatened on the counter as the ball was slipped through to Olexiy Kashchuk, who outsprinted Devenny but could not beat Pierce Charles with a low strike.
Northern Ireland should have done better with an opening nine minutes into the second half.
Shea Charles, who became the youngest Northern Ireland player to reach 40 caps at the age of 23 years and nine days, laid the ball off for a well-placed Galbraith, but he hung on to it for too long before playing in Price in a crowded box, with his shot lacking the power to beat Trubin.
Trai Hume then hit a daisy-cutter which Trubin pushed around the post, and from the resulting corner Galbraith teed up Devlin's goal.
It was when Hume took a blow to the head and started bleeding that Donley's protests to referee Francois Letexier earned him a costly yellow card, and a few minutes later O'Neill followed him into the book after overreacting to a foul on Ciaron Brown.
With time ticking down, Sikan hit a firm low shot from inside the box, but Pierce Charles somehow steered it around the post to preserve the win.