Romania (0) 14
Tincu had a big impact for Romania after coming on at half-time
Tries: Tincu, Corodeanu
Cons: Calafeteanu, Dumbrava
Portugal (7) 10
Portugal were denied their first World Cup win as Romania came from behind to edge a keenly fought Pool C match.
Romania made a host of mistakes in the opening half and Joaquim Ferreira went over to put Portugal ahead in Toulouse.
Portugal were strong in defence but their resistance was broken when Marius Tincu barged over with 16 minutes left.
Goncalo Malheiro put Portugal back in front with a penalty but Romania sealed the win through Florin Corodeanu's close-range try late on.
Portugal, playing in their first World Cup, had suffered heavy defeats in their opening three games but fancied their chances of victory following an error-strewn display by their opponents.
The Romanians dominated possession and territory but they could not get any momentum in the opening exchanges and had to rely on a succession of aimless punts forward.
And Ferreira made them pay with a try on 20 minutes as Romania threw long and wayward at a line-out.
Romania continued to try to get back into the game in the second half and the video referee turned down appeals for a try when Sorin Socol lost the ball as he was bundled over.
The gameplans for both sides were pretty much the same and with the backs seeing little of the ball, it was up to the forwards to make ground.
And abrasive hooker Tincu got Romania on the board with a try before Portugal's Malheiro made the score 7-10 with a penalty on 68 minutes.
With the Toulouse crowd roaring them on, Portugal battled to retain their advantage but Corodeanu's late score was just enough for his side to deny Portugal an historic victory.
Romania prop Bogdan Balan:
"It was a very important victory for us because it's our first victory at this World Cup.
"I want to congratulate the Romanian team because we believed in ourselves. And also Portugal, because they played very well.
"It will be a very difficult game for us against New Zealand because they are the best team in the world.
"I hope to reduce the number of handling mistakes. If they create turnovers, then it's very hard to stop them. We will try to make the best possible match and at least score a try."
Portugal coach Tomaz Morais:
"We played as we thought we could but we lost our way a little in the last quarter under the Romanian pressure.
"They had brought on some pretty tough forwards in the second half.
"We kicked well and forced them into mistakes but their players are more experienced than ours. Nevertheless we felt we would have won if it had not been our last match.
"A few weeks ago nobody would have believed we could have pulled off the results we did. We can be well satisfied with our first World Cup."
Romania: Dumitras; Nicolae, Dimofte, Gontineac, Fercu; Dumbrava, Calafeteanu; Popescu, Mavrodin, B Balan, Ratiu, Petre, Tudori, Manta, Tonita.
Replacements: Tincu, Ion, Socol, Corodeanu, Sirbu, Vlaicu, Brezoianu.
Portugal: Leal; Mateus, Sousa, Mateus, Portela; Cardoso Pinto, Jose Pinto; Cordeiro, Ferreira (capt), Spachuck, Goncalo Uva, Penalva, Coutinho, Joao Uva, Girao.
Replacements: Mure, Correia, Palha, Murinello, Pissarra, Malheiro, Carvalho.