Northern Ireland boss Michael O'Neill says the wins over Hungary and the Faroe Islands will instil confidence for the rest of the Euro 2016 campaign.
The men in green followed up their 2-1 success in Budapest with a 2-0 victory over the Faroes in Belfast on Saturday.
"We're delighted to have six points and now we believe we can go and take something from Greece," said O'Neill.
"We'll give it a go and do everything possible to keep up the momentum we've generated from the opening two games."
Northern Ireland lie two points ahead of Finland and Romania at the top of Group F after early goals from Gareth McAuley and Kyle Lafferty gave them victory on Saturday, but expect a stiff test away to the Greeks on Tuesday.
Greece will head into Tuesday's game badly in need of a win after Saturday's 1-1 away draw in Finland left them with only one point from their opening two matches after the 1-0 home defeat by Romania last month.
West Bromwich Albion winger Chris Brunt is unlikely to make the trip to Athens after pulling out of Saturday's match at Windsor Park with a groin injury sustained in training.
"We might make a few changes but we have a relatively youthful squad who are full of energy," explained O'Neill.
"I was very pleased with the quality and intensity of our play in the first half against the Faroes - the work we had done in training paid off and it was a good performance.
"Our emphasis was on pressing the opposition and the 2-0 scoreline at half-time didn't really do justice to the balance of play."
The hosts conceded a penalty 10 minutes before half-time but Roy Carroll saved Frodi Benjaminsen's spot-kick.
"We nearly gave them a lifeline they wouldn't have deserved but Roy made a great save - he's done well since he was recalled a couple of years ago and he's a big character in the dressing room," said O'Neill.
"Inevitably the tempo fell away a bit in the second half but we saw the game out."