Both sides are promising a more attacking approach than in their opening games, where the Northern Irish went down 1-0 to Poland and Ukraine were dispatched 2-0 by Germany.
The Ukrainians can at least take heart from the fact that they held the world champions to 1-0 until Bastian Schweinsteiger came on as substitute and scored in stoppage time. They also created chances of their own, at one point forcing a spectacular goal-line clearance.
Northern Ireland, by contrast, were a shadow of the side that qualified unexpectedly as winners of their group. They never looked like scoring against Poland and striker Kyle Lafferty, a lonely figure up front, lamented: "We didn't turn up today."
Coach Michael O'Neill has said the squad was devastated by the death of a 24-year-old fan, Darren Rodgers, in a fall from a sea-front railing in Nice early on Monday, and wants to make Thursday's game a "fitting tribute".
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With Germany waiting as their next opponents, the Ukraine fixture is Northern Ireland's best and perhaps only chance to pick up points.
"We have to be more aggressive," defender Jonny Evans told reporters on Tuesday.
Ukraine have strong attacking options of their own, through pacy wingers Andriy Yarmolenko and Yevhen Konoplyanka.
"We are still thinking about the starting line-up. There is time to choose the right tactics for the game but one thing is clear: we will attack. At the same time, we need to be accurate, especially at the back," assistant coach Andriy Shevchenko told the Football TV channel.
Ukraine midfielder Ruslan Rotan underlined the high stakes.
"Northern Ireland plays purely a British style, with great physical preparation, strong flanks, high crosses and lots of scrambling," he said.
"This will be a decisive game to define our prospects at the tournament."
(Additional reporting by Igor Nitsak and Padraic Halpin; Editing by Robin Pomeroy)
