First-half goals from Gareth McAuley and Kyle Lafferty - and a penalty save from Roy Carroll - saw O'Neill's men build on last month's victory over Hungary by beating the Faroe Islands 2-0 at Windsor Park on Saturday.
As a result, Northern Ireland top Group F and have started a qualifying campaign with back-to-back wins for the first time since 1968.
Saturday's success came in Northern Ireland's first home game in more than a year and went some way to banishing memories of draws at home against Luxembourg and Azerbaijan during qualifying for the World Cup.
"I am delighted obviously with the three points and the performance," O'Neill told Sky Sports.
"I thought in the first half we were absolutely superb, the quality of our play and the intensity of our play.
"We knew in the second half we probably wouldn't be able to maintain that but we still had total control of the game and saw the game out.
"We have momentum in this campaign and we missed the opportunity in the World Cup campaign to do that, with two home draws here, so we haven't missed that opportunity this time.
"We have taken it with the three points in Budapest and the three points tonight and we will try and add to that and keep the momentum that we have created in the opening two games."
Northern Ireland travel to Euro 2004 winners Greece on Tuesday and O'Neill believes confidence within his squad is growing.
"We are delighted with the six points," he added.
"We have two difficult games now away at Greece and Romania but the belief is developing in the squad all the time.
"Having gone to Hungary and won the game, the players will believe they are capable and going and getting something in Greece.
"We don't envisage an easy game at all, particularly coming off the back of this. Typically, the second game has been difficult for us, but we will have a real go."
