Romania gained instant revenge on Greece for beating them to World Cup qualification as Ciprian Marica's penalty sealed a 1-0 win.
Marica netted from the spot after 10 minutes to give the visitors a victorious start to their Euro 2016 qualifying campaign.
The striker was later sent off, but his side held on to defeat the side who beat them in a play-off for a place in Brazil.
Greece reached the last 16 at the World Cup, going out only on penalties to Costa Rica, but they were quickly on the back foot in their Group F opener on Sunday night.
Jose Holebas brought down Alexandru Chipciu in the area to concede a penalty and Marica stepped up to slot his shot low into the left corner.
The visitors continued to have the better of the match, Alexandru Maxim firing wide from long range and then picking out Dragos Grigore with a corner, but the defender's header was saved by Orestis Karnezis.
Marica picked up a yellow card for time-wasting in first-half stoppage-time and it proved a costly one as just nine minutes into the second half he picked up another for a foul and was dismissed.
The Greeks sensed a chance to get back into the match,.
Panagiotis Kone's header was blocked by Ciprian Tatarusanu in the Romania goal, while with just two minutes to go Vassilis Torosidis crashed a shot against the bar.
That was as close as the home side got, though, as Romania kept them out to record an impressive win.