Michael O'Neill's side managed a 1-1 draw in the Dragao in Porto on Tuesday night. They have achieved famous wins before in recent years, particularly over England and Spain. They were a long way from Windsor Park but still produced a performance of remarkable commitment and organisation.
Still early into O'Neill's tenure as manager, he was delighted with his players, who were still leading with 11 minutes left.
"This is a team that is in its infancy in many ways, it's a transitional period for us, so to see them play with that spirit and discipline makes me immensely proud," said O'Neill, who won two League of Ireland titles with Shamrock Rovers before taking this job last year.
"We have experienced players but also young and inexperienced players at club and international level, but we've done a lot of work and you've seen it pay off. This is a group who want to learn and progress and have nights like this, to perform for Northern Ireland and make people proud of them again."
Northern Ireland are unlikely to finish first or second in a group including Portugal and Russia but can be delighted with their progress. "We said before the game that the most important thing was not to let anyone question their character," said O'Neill. "They certainly did that from one to 11, and there are also lads who didn't get involved in the match who have worked hard all week too. It was a huge success for us and hopefully a step in the right direction."
O'Neill had special praise for his captain, Jonny Evans, who was heroic in defence, as were Aaron Hughes and Craig Cathcart: "He is going to be a leader of men and a leader of this team."
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