Michael O'Neill's Northern Ireland will need to produce a colossal performance in Switzerland on Sunday if they are to end a three-decade absence from the World Cup finals.
Chasing a first appearance at the tournament since 1986, they trail 1-0 in their play-off with the Swiss after referee Ovidiu Hategan controversially gave a penalty in Belfast for a handball against Corry Evans, who had his arms tucked in when Xherdan Shaqiri's shot appeared to strike his back from close range.
Here Press Association Sport details some of the talking points ahead of the second leg.
Northern Ireland's sense of injustice
Swiss midfielder Granit Xhaka does not understand the continued fuss and O'Neill himself has urged his players not to dwell on it, but the fact Northern Ireland were victims of a refereeing blunder in the first leg on Thursday is inescapable. They should not forget about why they are behind in this tie, and instead channel that anger to drive them on at St Jakob-Park. It is an emotion that can spur Northern Ireland on, as it seemed to in the second half at Windsor Park, and they must go down fighting rather than accepting their fate has already been sealed by one blow of Hategan's whistle.
Northern Irish changes
O'Neill will be forced to make at least one change due to Evans being suspended. Do not be surprised if there are others given this is a boss that made five alterations for the key Euro 2016 game against Ukraine. The likes of George Saville, Paddy McNair, Jamie Ward, Conor Washington and Aaron Hughes will all come into his thinking. Stuart Dallas is a big injury concern too having not trained on Saturday so there may be a formation tinker from O'Neill. He has to find a way to ask more questions of the Swiss backline after his team failed to register a single shot on target in Belfast.
Switzerland's dominant home form
Over the past nine years only England have ever won a competitive game on Swiss soil. They have done so twice, with a 3-1 victory in 2010 followed up by a 2-0 success in 2014, but since 2008 no other country has been able to do what Northern Ireland must. Following England's most recent success, Switzerland have won all nine of their home qualifiers, kept seven clean sheets and have scored 30 and conceded just four.
The end of the road?
This will be the last shot at reaching the World Cup for many of Northern Ireland's players, and could be the final time they pull on the green shirt full stop. Hughes, who turned 38 this week, and fellow defender Gareth McAuley, who turns 38 next month, would be the most likely candidates to call it a day if their country do not make it to Russia, while Chris Brunt, 32, could also fall into that category. Then there is manager O'Neill. With his stock high, perhaps he will be tempted into another post after this and the rebuilding job is left to someone else.