Ciaron Brown scored twice, while Isaac Price added the other goal as Northern Ireland moved to the top of Group B2.
Brown gives Northern Ireland early lead
Northern Ireland made a dream start when Brown opened the scoring in the ninth minute.
The Oxford United defender reacted quickest inside the penalty area to put Michael O'Neill's side in front and register his first senior international goal.
Ukraine struggled to respond as Northern Ireland remained organised and dangerous on the counter.
Price doubles the advantage
Northern Ireland extended their lead in the 22nd minute through Isaac Price.
The young midfielder finished a well-worked attacking move to give the visitors a 2-0 advantage before half-time.
Ukraine were unable to find a way back into the contest despite attempting to increase the pressure.
Brown completes his brace
Brown struck again in the 61st minute to effectively settle the contest.
The defender got a decisive touch on a free-kick from goalkeeper Pierce Charles and the ball travelled towards the Ukraine goal before goalkeeper Dmytro Riznyk was unable to prevent it from finding the net.
The second goal completed Brown's first international brace and gave Northern Ireland a commanding 3-0 lead.
Northern Ireland move top of Group B2
The victory takes Northern Ireland to seven points from three matches, putting them top of Group B2.
Ukraine remain on four points after three matches, having opened their campaign with a 1-0 victory over Hungary before drawing 0-0 with Georgia.
Northern Ireland will face Georgia in their next Nations League fixture on Monday, while Ukraine will host Hungary on the same day.
Match details
• Ukraine: No goals
• Northern Ireland: Ciaron Brown 9', 61', Isaac Price 22'
• Venue: Stadion Antona Malatinského, Trnava, Slovakia
• Competition: UEFA Nations League, League B, Group B2
• Date: 2 October 2026