The team have beaten Hungary and the Faroe Islands in their first two outings, leaving them at the top of Group F ahead of their match against Greece tomorrow.
The manager told reporters: "We've never said we think we can win the group or anything like that, but the belief is in this squad that they are more than capable of competing.
"I believe in the team. I think there is a sense that some people can get carried away and we are looked at as all conquering, but you have to be sensible also and recognise that Greece are the number one seed in the group.
"When we looked at the fixtures when they came out and our best chances of getting points this wouldn't have been a game we would have looked at. But the start has given us the belief that we can come here and add to our points tally."
Northern Ireland are currently ranked 36th in the world by FIFA, with the Faroe Islands the only side in their group ranked lower than them.