Their 2-0 defeat to Germany in Windsor Park on Monday - in a match that they stayed right in until injury time - leaves in a hard situation with their final three games to come against the Group C heavyweights - home and away to the Netherlands and a trip to Germany.
Defender Marcel Halstenberg drilled the ball in three minutes after halftime following a lackluster first half by Germany, who lost 4-2 at home to the Netherlands on Friday last week.
Germany now leapfrog Northern Ireland to go top of Group C on goal difference, with both sides having picked up 12 points from their opening five games.
"After the defeat against Holland, we were under pressure today and had to overcome some difficulties", said Germany boss Loew.
"We had to overcome a few problems in the game - the Northern Irish were courageous and attacked us early on", said Loew, and admitted that his team should have killed the game off earlier.
"It wasn't a good match for us, especially the second half when we didn't take any chances", coach Zlatko Dalic told television channel HRT.
Germany, missing half a dozen injured players, seemed to lack a clear game plan in the first half as they struggled to find ways to open up the hosts' defense.
Ronald Koeman's side still have work to do to reach a first major final since making the 2014 World Cup semi-finals, though, as they trail second-placed Northern Ireland by three points in Group C, albeit with a game in hand.
"We have some problems to explore", said the Borussia Dortmund midfielder. "So we will need some patience because this a learning process".
Conor Washington forced an early save from goalkeeper Manuel Neuer, and almost bundled the ball in at a goalmouth scramble shortly before half-time.
Timo Werner had the visitors' best chance before the break but his close-range effort was saved by Bailey Peacock-Farrell.
"We managed to stop them building the game and got joy off pressing and winning the ball higher up the pitch", the hosts' coach Michael O'Neill told Sky. 'Whenever he does hang up his boots, which hopefully will be after I've left this job, he will rightly be remembered as one of the greatest players we've ever had.