Just four spots left in Europe: All you need to know about the World Cup 2018 play-offs

Eight European nations. Four spots left at next summer's World Cup finals in Russia. Everything to play for.

Northern Ireland, aiming for their first World Cup finals since 1986, face Switzerland in Belfast on Thursday as the two-legged play-offs begin.

The Republic of Ireland meet Denmark, with the first leg in Copenhagen, in one of the other three ties as they seek to reach a first World Cup finals since 2002.

Four-time world champions Italy are in danger of missing out for the first time since 1958 as they take on Sweden, while either Croatia or Greece will complete the European contingent.

These teams were the eight best second-placed finishers in the nine European qualifying groups, with Denmark, Switzerland, Italy and Croatia seeded because of their superior world rankings.

Northern Ireland vs Switzerland

First leg: Thursday, 9 November (20:45 CET), Belfast

Second leg: Sunday, 12 November (18:00 CET), Basel

Northern Ireland and Switzerland have not met in a competitive fixture since 1964.

Michael O'Neill's side, who are targeting back-to-back tournament appearances after reaching the last 16 at Euro 2016, finished second behind world champions Germany in Group C.

Switzerland had a 100% record in the group stages before a 2-0 defeat by Portugal in their final qualifier saw them miss out on top spot on goal difference.

"The most important thing is we don't concede an away goal," O'Neill said. "We'll be prepared for Belfast. We've only lost one game there in four years.

"We knew it was going to be difficult. They've had a good campaign, but we have a big opportunity to get to Russia. We know we'll have to be at our best but we believe we're good enough to do that."

Stats

Northern Ireland have won four of their past five competitive home games, but have lost their past two away matches

Switzerland won nine of 10 Group B qualifiers, missing out to Portugal on goal difference

Denmark vs Republic of Ireland

First leg: Saturday, 11 November (20:45 CET), Copenhagen

Second leg: Tuesday, 14 November (20:45 CET), Dublin

The Republic of Ireland may have qualified for back-to-back European Championships, but have not featured on the biggest stage of all since a buoyant showing at the 2002 World Cup.

West Brom winger James McClean's second-half goal earned a victory in Wales last month to send them into the qualifying play-offs at the expense of their hosts.

Denmark, who last qualified in 2010, finished second behind Poland in their qualifying group.

"Naturally, we're just pleased to be in the draw," Republic manager Martin O'Neill said.

"Being one of the unseeded teams means it was always going to be a difficult tie. We're delighted to be in it."

stats

Denmark have lost one of their last eight competitive home matches, winning four and drawing three

The Republic are unbeaten in six competitive away games, winning three and drawing three

Sweden vs Italy

First leg: Friday, 10 November (20:45 CET), Stockholm

Second leg: Monday, 13 November (20:45 CET), Milan

A World Cup finals without four-time winners Italy, whose only failure to qualify came back in 1958, is almost unthinkable for many football fans.

The Azzurri also came close to missing out when England pipped them in their 1998 World Cup qualifying group, and they needed a 2-1 play-off win against Russia to scrape through.

Many Italian fans are fearing the worst after some lacklustre recent performances, including a humbling 3-0 defeat in Spain and embarrassing 1-1 home draw against Macedonia, but veteran coach Gian Piero Ventura says that failure to reach Russia has not crossed his mind.

"Going to the World Cup is important for everyone, the young and the not-so-young," said the 69-year-old.

"I have never considered the possibility of not going to the World Cup. Italy has never let us down and we won't let Italy down."

After missing out on the past two tournaments, Sweden could fail to qualify for three consecutive World Cup finals for the first time.

The Swedes finished behind France in Group A but clinched runners-up spot ahead of the Netherlands, who needed to win by seven clear goals to overtake them in the final game.

Stats

Sweden are unbeaten in seven competitive home matches, winning six and drawing one

Italy have won just two of their past four matches

Croatia vs Greece

First leg: Thursday, 9 November (19:45 GMT), Zagreb

Second leg: Sunday, 12 November (19:45 GMT), Pireaus

Croatia have won all four of their previous play-off ties - to reach either World Cup or European Championship tournaments - and have booked a place at nine out of 11 major finals as an independent nation.

They clinched second place in Group I with a 2-0 win in Ukraine in their final match, following a turbulent campaign, with coach Ante Cacic sacked and replaced by Zlatko Dalic before the deciding game.

"Winning the first leg would make life so much easier in the return fixture," Croatia winger Ivan Perisic said.

"The Greeks will certainly be defensive and try as hard as they can to keep a clean sheet, but we have enough up our sleeve up front in an effort to swing the tie our way in Zagreb.

"It's down to us, just as it was against Ukraine. The new coach injected fresh ideas and we did the best job we could in that vital game."

Greece, who finished behind Belgium in Group H, are aiming for a third straight World Cup finals after reaching the knockout phase for the first time at Brazil 2014.

They are hoping captain Vasilis Torosidis and central defender Sokratis Papastathopoulos are fit for the first leg, while Roma defender Kostas Manolas is suspended after a fair play violation.

Fifa ruled Manolas deliberately got himself booked in a 2-1 win over Cyprus - and served a suspension in the final group match against Gibraltar - so he would begin the play-offs with a clean disciplinary record.

Stats

Croatia are unbeaten in 11 competitive home games, winning eight and drawing three

Greece did not lose an away qualifier, winning three and drawing two

Which European nations have already qualified?

Five-time winners Brazil have also qualified, along with Argentina, Colombia, Costa Rica, Egypt, Iran, Japan, Mexico, Nigeria, Panama, Saudi Arabia, South Korea and Uruguay.

Who else can still qualify?

The tournament will consist of 32 teams, with hosts Russia joined by 31 qualifiers from around the globe.

We already know 23 of the nations who will compete next summer, plus the four European play-off winners.

That leaves five more spots to be decided:

Peru or New Zealand (South America/Oceania play-off)

Honduras or Australia (CONCACAF/Asia play-off)

Tunisia or Congo (African Group A winners)

Morocco or Ivory Coast (African Group B winners)

Senegal or Burkina Faso or Cape Verde or South Africa (African Group D winners)

Road to Russia: The key dates

9-11 November: Play-off first legs

12-14 November: Play-off second legs

1 December: Groups are drawn

14 June - 15 July 2018: World Cup