This is where it gets exciting in the tournament, especially for Switzerland.
They've been defensive so far in this tournament so it will be interesting to see how they approach today - but Spain have to react after that performance against Japan.
Get Involved
#bbcfootball, WhatsApp 03301231826, text 81111 (UK only, standard rates apply)
With the knockout games starting today, don't forget to let us know your thoughts on Saturday's matches - and, indeed, the entire tournament.
Who's going all the way to lift the trophy later this month?
Get in touch via the usual methods on laptop, tablet, mobile or any other device you possess.
Getty ImagesCopyright: Getty Images
'Super Saturday'
Switzerland v Spain (06:00 BST)
Neil Johnston
BBC Sport at Eden Park
BBC SportCopyright: BBC Sport
This game in Auckland forms part of a 'Super Saturday' of sport in New Zealand.
Now the Football Ferns have been knocked out of the Fifa Women's World Cup, attention has turned to the Silver Ferns.
There is big support for the team playing at the Netball World Cup in South Africa, with a huge semi-final for New Zealand against England taking place at 9pm here.
With the All Blacks beating Australia in Dunedin earlier, and Wellington hosting Japan against Norway in the Women's World Cup later, it is wall-to-wall sport on the local TV networks.
Spain 'won't forget Japan loss'
Switzerland v Spain (06:00 BST)
Spain manager Jorge Vilda wants his team to be energised by their heavy group-stage loss to Japan when they face Switzerland.
"These types of defeats leave a deep mark upon us," Vilda said.
"But they are also necessary in the evolutionary development of the team and process of growth.
"We haven't forgotten about it and we will not forget about it."
Watch live on the BBC
BBC One
This game is live on BBC One, iPlayer and online, with build up beginning at 05:45 BST so if you are up and about early tune in!
Second deadly shooting
Switzerland v Spain (06:00 BST)
Neil Johnston
BBC Sport at Eden Park
Since the last World Cup game here in New Zealand's largest city on Tuesday, there has been another shooting about a five minute walk from the Fifa fan festival.
One person has died in hospital after two people were shot in Queen Street, which is home to some of Auckland's most exclusive shops.
It is the second deadly shooting here in two weeks after an incident on a construction site in the central business district just hours before the start of the tournament.
Following the latest incident on Thursday night, and with thousands of football fans in the city for today's game, there is a visible police presence on the streets to reassure the public.
Eden Park is about a 20 minute train journey from the city centre.
Team news
Switzerland v Spain (06:00 BST)
Switzerland are unchanged from the side that started the 0-0 draw with co-hosts New Zealand last Sunday.
That means Arsenal duo Noelle Maritz and Lia Walti both start.
Midfielder Walti is captain of Switzerland.
.Copyright: .
There is some surprising news from the Spain dressing room as Jorge Vilda reacts to the 4-0 defeat to Japan last Monday by making five changes.
Keeper Cata Coll makes her senior international debut in a World Cup last 16 tie in place of first-choice Misa Rodríguez.
And Alexia Putellas, the two-time Ballon d'Or winner is dropped to the bench.
.Copyright: .
Big numbers for World Cup of surprises
Switzerland v Spain (06:00 BST)
Neil Johnston
BBC Sport at Eden Park
As two-time world champions Germany head home and Morocco, Jamaica, Nigeria and South Africa all get ready for the knockout stage, this has been a World Cup of surprises.
And the crowds are loving it. A total of 1,222,839 were inside the stadiums in Australia and New Zealand for the 48 group games. That is an average crowd of 25,476 per match.
According to Fifa, 1,715,000 tickets have now been sold for the tournament. Over in China, 53.9m viewers watched on TV as the national team lost 6-1 to England on 1 August.
Post update
Getty ImagesCopyright: Getty Images
Hello!
It is very, very, very early here in the UK but a bit of knockout football is a good way to shake off the tiredness.
After a thrilling group stage, the last-16 gets under way today as Group A winners Switzerland face Spain, who finished second in Group C.
Unlike Germany, Brazil and Canada, Spain managed to avoid an early exit but the world number six have still been on the wrong end of surprise results, having lost 4-0 to Japan in their final group game.
Switzerland, meanwhile, are unbeaten so far at the tournament, progressing thanks to one win and two draws during the group stage.
Sunshine and blue skies
Switzerland v Spain (06:00 BST)
Neil Johnston
BBC Sport at Eden Park
BBC SportCopyright: BBC Sport
How's the weather back home?
It's still winter in New Zealand but you wouldn't know it taking a stroll around Auckland today, where families have been out in T-shirts and the waterside cafes and bars have been busy.
Temperatures have peaked in the high teens and we've got blue skies over Eden Park but it will soon be dark and the temperatures are set to dip.
This games kicks-off at 5pm local time and it could be close to 8pm before we know the winner if it goes to extra-time and penalties.
BBC SportCopyright: BBC Sport
Post update
Getty ImagesCopyright: Getty Images
It has been a World Cup of surprises so far with some big names heading home.
Spain, however, managed to navigate through the group stage but they can ill afford to relax as they face Switzerland this morning in the first game of the knockouts.
Live Reporting
Gary Rose
All times stated are UK
'Spain have to react'
Switzerland v Spain (06:00 BST)
Steph Houghton
Manchester City defender on BBC One
This is where it gets exciting in the tournament, especially for Switzerland.
They've been defensive so far in this tournament so it will be interesting to see how they approach today - but Spain have to react after that performance against Japan.
Get Involved
#bbcfootball, WhatsApp 03301231826, text 81111 (UK only, standard rates apply)
With the knockout games starting today, don't forget to let us know your thoughts on Saturday's matches - and, indeed, the entire tournament.
Who's going all the way to lift the trophy later this month?
Get in touch via the usual methods on laptop, tablet, mobile or any other device you possess.
'Super Saturday'
Switzerland v Spain (06:00 BST)
Neil Johnston
BBC Sport at Eden Park
This game in Auckland forms part of a 'Super Saturday' of sport in New Zealand.
Now the Football Ferns have been knocked out of the Fifa Women's World Cup, attention has turned to the Silver Ferns.
There is big support for the team playing at the Netball World Cup in South Africa, with a huge semi-final for New Zealand against England taking place at 9pm here.
With the All Blacks beating Australia in Dunedin earlier, and Wellington hosting Japan against Norway in the Women's World Cup later, it is wall-to-wall sport on the local TV networks.
Spain 'won't forget Japan loss'
Switzerland v Spain (06:00 BST)
Spain manager Jorge Vilda wants his team to be energised by their heavy group-stage loss to Japan when they face Switzerland.
"These types of defeats leave a deep mark upon us," Vilda said.
"But they are also necessary in the evolutionary development of the team and process of growth.
"We haven't forgotten about it and we will not forget about it."
Watch live on the BBC
BBC One
This game is live on BBC One, iPlayer and online, with build up beginning at 05:45 BST so if you are up and about early tune in!
Second deadly shooting
Switzerland v Spain (06:00 BST)
Neil Johnston
BBC Sport at Eden Park
Since the last World Cup game here in New Zealand's largest city on Tuesday, there has been another shooting about a five minute walk from the Fifa fan festival.
One person has died in hospital after two people were shot in Queen Street, which is home to some of Auckland's most exclusive shops.
It is the second deadly shooting here in two weeks after an incident on a construction site in the central business district just hours before the start of the tournament.
Following the latest incident on Thursday night, and with thousands of football fans in the city for today's game, there is a visible police presence on the streets to reassure the public.
Eden Park is about a 20 minute train journey from the city centre.
Team news
Switzerland v Spain (06:00 BST)
Switzerland are unchanged from the side that started the 0-0 draw with co-hosts New Zealand last Sunday.
That means Arsenal duo Noelle Maritz and Lia Walti both start.
Midfielder Walti is captain of Switzerland.
There is some surprising news from the Spain dressing room as Jorge Vilda reacts to the 4-0 defeat to Japan last Monday by making five changes.
Keeper Cata Coll makes her senior international debut in a World Cup last 16 tie in place of first-choice Misa Rodríguez.
And Alexia Putellas, the two-time Ballon d'Or winner is dropped to the bench.
Big numbers for World Cup of surprises
Switzerland v Spain (06:00 BST)
Neil Johnston
BBC Sport at Eden Park
As two-time world champions Germany head home and Morocco, Jamaica, Nigeria and South Africa all get ready for the knockout stage, this has been a World Cup of surprises.
And the crowds are loving it. A total of 1,222,839 were inside the stadiums in Australia and New Zealand for the 48 group games. That is an average crowd of 25,476 per match.
According to Fifa, 1,715,000 tickets have now been sold for the tournament. Over in China, 53.9m viewers watched on TV as the national team lost 6-1 to England on 1 August.
Post update
Hello!
It is very, very, very early here in the UK but a bit of knockout football is a good way to shake off the tiredness.
After a thrilling group stage, the last-16 gets under way today as Group A winners Switzerland face Spain, who finished second in Group C.
Unlike Germany, Brazil and Canada, Spain managed to avoid an early exit but the world number six have still been on the wrong end of surprise results, having lost 4-0 to Japan in their final group game.
Switzerland, meanwhile, are unbeaten so far at the tournament, progressing thanks to one win and two draws during the group stage.
Sunshine and blue skies
Switzerland v Spain (06:00 BST)
Neil Johnston
BBC Sport at Eden Park
How's the weather back home?
It's still winter in New Zealand but you wouldn't know it taking a stroll around Auckland today, where families have been out in T-shirts and the waterside cafes and bars have been busy.
Temperatures have peaked in the high teens and we've got blue skies over Eden Park but it will soon be dark and the temperatures are set to dip.
This games kicks-off at 5pm local time and it could be close to 8pm before we know the winner if it goes to extra-time and penalties.
Post update
It has been a World Cup of surprises so far with some big names heading home.
Spain, however, managed to navigate through the group stage but they can ill afford to relax as they face Switzerland this morning in the first game of the knockouts.