Mykhaylo Fomenko's team inflicted Romania's first loss since June 2014 and showed Ukraine should not be taken lightly after they scored four times in 15 minutes in Turin against a team who had conceded just two goals in their qualifying campaign.
Romania coach Anghel Iordanescu made nine changes from the 1-1 draw against Democratic Republic of Congo in their last warm-up game on Wednesday, with captain Vlad Chiriches and midfielder Mihai Pintilii the only survivors.
Iordanescu's side took the lead in the 23rd minute when Gabriel Torje fired a thunderous shot past keeper Andriy Pyatov from just outside the area for his 10th international goal.
Ukraine levelled two minutes before the break when Roman Zozulya slid in at the far post after central defender Chiriches failed to clear Vyacheslav Shevchuk's cross from the left and keeper Ciprian Tatarusanu should have done better.
Young Ukraine midfielder Oleksandr Zinchenko who got a late call-up, made it 2-1 with his debut goal three minutes after the interval, capitalising on more poor defending by Chiriches.
The tricky Yehven Konoplyanka added a third for Ukraine six minutes later and Andriy Yarmolenko made it 4-1 on the hour when Konoplyanka turned provider.
MORE RESPECTABLE
Romania, who conceded four for the first time since a 4-0 defeat by the Netherlands in March 2013, cut the deficit when Denis Alibec scored a debut goal in the 75th before a Nicolae Stanciu strike 10 minutes later made the score more respectable.
Alibec netted a superb free kick 17 minutes after coming on while Stanciu scored his third goal in four internationals.
"It was a good first half in which we controlled the game -- we created chances and we managed to score," Romania coach Anghel Iordanescu told Digi Sport TV.
"But then we committed big individual mistakes, horrible mistakes. I can't forget the mistakes, made by experienced players. Thanks to the changes in the second half, we managed to get back in the game and score twice."
The teams play their final friendlies on Friday when Romania host Georgia in Bucharest and Ukraine meet Albania in Bergamo.
Romania play hosts France in the tournament opener on June 10 in Paris and also face Switzerland and Albania in Group A.
Ukraine have been drawn in Group C with world champions Germany, Poland and Northern Ireland.
