Northern Ireland secured second spot in Group C with a 2-0 win over Czech Republic at Windsor Park on Monday.
Michael O'Neill's side went into the game knowing a point would be enough to see them clinch the place and give themselves a fantastic chance of making the World Cup qualifying play-off round.
The three points were ultimately wrapped up in the first half with Jonny Evans heading home in the 28th minute before Chris Brunt curled home a superb free kick 13 minutes later.
The Czech Republic pushed for goals in the second half but could not breach one of the most solid defences in the European World Cup Qualifiers as Northern Ireland secured the vital victory.
The hosts could have struck in the opening minutes as Josh Magennis headed a Brunt corner wide in the pick of the early action. Despite seeing the better of the ball, Czech Republic struggled to create first-half chances, with the best coming in the 22nd minute as Jan Boril headed towards goal from the left of the box but Michael McGovern made an easy save.
The hosts broke the deadlock six minutes later, with a Brunt corner again causing the Czech defence some problems. The delivery was initially cleared by the visitors, but Oliver Norwood was lurking at the top of the box to head the ball back towards goal. His effort found Jonny Evans at the back post, who flicked the ball home with the back of his head.
Brunt added his own goal in the 41st minute with a superb free kick. Corry Evans was fouled by Filip Novak around 20 yards out to hand Northern Ireland the advantage, which was expertly curled home by the West Brom midfielder.
Czech Republic could have halved the deficit just after the hour mark as Josef Husbauer curled a superb cross into the box from the top left corner, searching for Michal Krmencik in the middle but he could not rise high enough to meet it as McGovern ushered the ball out of play.
The visitors were camped in Northern Ireland's half for much of the second period and had two of the best chances in quick succession in the 68th minute. Theodor Gebre Selassie's fizzing cross evaded the foot of Jan Kliment before Norwood cleared. The ball then fell to Vladimir Darida, but his long range effort went well over the crossbar.
But despite seeing 77 per cent of the ball, Czech Republic could not find a way past Northern Ireland - who have conceded just two goals in their eight qualifiers so far - as the hosts made sure they will finish in the top two of Group C along with Germany.
Match stats
Northern Ireland are now unbeaten in nine competitive games at home, winning seven and drawing two.
Northern Ireland enjoyed just 23 per cent of possession, their lowest figure in the 2018 World Cup Qualifying campaign so far.
Michael O'Neill has now won 14 competitive matches as Northern Ireland boss, as many as the two previous managers, Nigel Worthington and Lawrie Sanchez, combined.
Jonny Evans netted just his second goal for Northern Ireland and his first in 45 games, since netting against Poland in March 2009.
Man of the match - Chris Brunt
It was a superb Northern Ireland performance all round but Chris Brunt had a hand in both goals and put in a defensive shift as Czech Republic probed in the second half.
It was his corner that started off the play for the first goal and scored a fantastic second-half free-kick, with most of his set piece deliveries causing problems for the visiting defence.
After his Euro 2016 heartbreak, Brunt has had a huge hand in getting Northern Ireland into a great position to qualify for their first World Cup since 1986 and appearances in successive major tournaments, having been directly involved in four goals in his five qualifying appearances so far (2 goals, 2 assists).
What next?
Northern Ireland welcome Germany to Windsor Park on Thursday 5 October and, if they beat the current World Cup holders, they would be in with a chance of winning the group.
This would require them to also pick up three points in their final group qualifier away to Norway on Sunday 8 October, and hope that Germany draw or lose to Azerbaijan.
However, even if this does not happen, they are still certain of a second-place finish and should secure their spot in the play-off round which begins in November.