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Northern Ireland beat Azerbaijan 4-0 on Friday night to go second in Group C with seven points from four matches.
They are five points behind Germany and O'Neill described the game against the Norwegians on 26 March as "huge".
"We have had a good start to the group, and we have been to Germany and the Czech Republic," O'Neill added.
"A win will put us a good distance ahead of Norway, and Azerbaijan will play Germany," he said.
"The fifth game is always crucial. Once you get to 10 points you are in touching distance to get enough points to possibly get there, that's what we have to aim to do.
"We have been very good at home, not only in this campaign but in the previous campaign, and the fact the next game is here is a bonus as well."
Kyle Lafferty, Gareth McAuley, Conor McLaughlin and Chris Brunt got the goals as the previously unbeaten Azerbaijan were dispatched with surprising ease in Belfast.
O'Neill's men had lost, drawn and won going into their fourth qualifier on Friday, including a 4-0 win over San Marino on October 8.
"We had emphasised that it would not be as straightforward as San Marino, we had too much respect for Azerbaijan," said O'Neill, whose men who face Croatia in a Belfast friendly on Tuesday night.
"But we knew if we got forward in the right areas and crossed the ball we could cause them problems and that was the case, whether it was from open play or set-pieces.
Meanwhile, Azerbaijan manager Robert Prosinecki felt his team, who are third, were still in contention for a place in the finals in Russia.
"I think we are a good team, that's hard to say after we've been beaten 4-0 but I still think we have a lot of talent," he said.
"We could have done more up front but it is not a matter of despair. We have seven points from four games, three away from home, so it's all to play for."
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Northern Ireland's game at home to Norway will be pivotal in their attempt to qualify for the 2018 World Cup, says manager Michael O'Neill.