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The 0-0 draw means O'Neill's side stay second in Group F and on course to reach next summer's finals in France.
"It probably strengthens our chances of being in the top three as we are nine points ahead of Finland with four games left," said O'Neill.
"The aim has to be keep ahead of the team immediately below us, Hungary."
O'Neill admitted it was not a sparkling display at a Windsor Park ground where only two stands were in operation because of major redevelopment.
But the points leave Northern Ireland on 13 from six games, one behind Romania and two ahead of Hungary in what is a three-team scrap for the two automatic qualification places.
O'Neill's men next face the Faroe Islands away on 4 September, followed three days later by Hungary at home.
"That will be an interesting double header but I think we are well equipped for it," added O'Neill.
"Hungary have to go to Romania first in Budapest and that is going to be a huge game.
"You always want to just keep some distance between you and the team beneath you, which is Hungary.
"Our focus has to be on winning the match away to the Faroe Islands and that is no easy task because we saw Greece went there tonight and were beaten.
"It is going to be a tough game on an artificial surface but hopefully we will get a positive result and come here with a massive carrot to play for against Hungary."
Northern Ireland boss Michael O'Neill was pleased to have bagged a precious point against Romania in Belfast in the push for Euro 2016 qualification.