Northern Ireland started their World Cup bid with a 3-1 win in Luxembourg.

Jamie Reid's early opener was cancelled out by Aiman Dardari, but goals from Shea Charles and Justin Devenny gave Northern Ireland the win.

However, Group A was blown wide open when Slovakia defeated Germany 2-0 in Bratislava.

Many had tipped the Germans to top the group and qualify automatically with ease, but Julian Nagelsmann's side ended the opening round of fixtures bottom of the pile.

They were under big pressure in their second game as Isaac Price brought Northern Ireland level in Frankfurt after Serge Gnabry's opener.

A defensive mistake allowed Nadiem Amiri and a Florian Wirtz stunner, both of which came in the space of three minutes, saw the Germans through on the night.

In the other game, Slovakia needed a 90th-minute winner from Tomas Rigo to battle past Luxembourg.

The easiest way to qualify for the World Cup is to top the group and earn automatic qualification, while the runner-up in each group will progress to the play-off round.

While finishing in the top two would make life straightforward for Northern Ireland, they could still earn a play-off due to winning their Nations League group last year.

The top four Nations League winners who do not finish in the top two in their World Cup qualifying group will earn a play-off place.

O'Neill's side are currently in second after two matches, but let's talk the hypothetical worst-case scenario and Northern Ireland finish outside of the top two come the end of Group A in November.

In terms of ranking, Northern Ireland finished 12th out of the 14 group winners in the Nations League, which means they need eight of the 11 teams above them to qualify or have already booked a play-off spot.

You would expect Germany to finish in the top two despite their rocky start, but if they don't then it's a win-win as Northern Ireland would be the team most likely to finish ahead of them.

In the remaining groups, seven teams are in the top two with two rounds of matches remaining, and that would be enough for Northern Ireland to secure a play-off regardless of the final standings in Group A.

Spain, Portugal, France and England should be near certainties to qualify.

Erling Haaland's Norway currently lead the way in Group I, while the Czech Republic are very well placed in Group L and are tied at the top with Croatia.

At least one of North Macedonia and Wales - who are in a similar but slightly less precarious position to Northern Ireland due to their higher Nations League ranking - should finish in the top two of Group J, and both finishing above Belgium would be a dream scenario for NI.

Sweden have made a slow start to Group B and are third behind Switzerland and Kosovo after two matches, while Romania are also outside the top two in Group H behind leaders Bosnia-Herzegovina and Austria in second.

Northern Ireland are back in action with a home double-header in October.

Slovakia come to Belfast on 10 October and while it's not quite win or bust, it could make or break Northern Ireland's hopes of finishing in the top two.

A victory over Slovakia, and assuming Germany beat Luxembourg as expected, would leave three teams on six points at the halfway mark of the campaign.

Then, Germany visit Belfast on where O'Neill's youthful side will look to cause an upset and make amends for the defeat in Cologne.

Northern Ireland finish their campaign in November with a trip to Slovakia and finish at home to Luxembourg on 17 November.

If they reach the play-offs, one-legged semi-finals and a final will take place in March before the finals in the USA, Mexico and Canada start in June.