The first World Cup hosted by an Arab nation enters its knockout phase on Saturday, but such has been the daily rollercoaster of shocks, comebacks and head-spinning group climaxes that everyone involved should perhaps lie down for a week in a dark room before carrying on.

Forty-eight games and 120 goals into the latest edition of FIFA's showpiece and there has barely been a dull moment at a tournament that just keeps giving.

The last three nights of simultaneous group action were mind-boggling, with Japan stunning Spain to qualify from Group E and South Korea scoring a stoppage-time winner to beat Portugal and make it out of Group H.

Four-time champions Germany, on the other hand, are going home, still scratching their heads at how.

PHOTO: REUTERS

The tournament began with a glitzy ceremony and a tame opening game between Qatar and Ecuador, when the narrative still very much centred on the controversial host nation's treatment of migrant workers and the LGBT+ community.

That debate will continue after the final ball is kicked, but as far as what has happened inside the eight gleaming stadiums, the World Cup has been a stunning spectacle.

England's 6-2 hammering of Iran on day two and France's Kylian Mbappe-inspired 4-1 defeat of Australia were the early headline acts. Then the script was flipped upside down.

When Lionel Messi gave Argentina the lead from the penalty spot in their opening Group C match against Saudi Arabia, all seemed normal. But Saleh Al-Shehri and Salem Al-Dawsari sealed a 2-1 Group C win for the 51st-ranked Green Falcons that, according to data company Nielsen Gracenote, was the biggest statistical shock in World Cup history.

PHOTO: REUTERS

Normal service resumed a day later when Spain thumped Costa Rica 7-0, but hours later Japan's Samurai Blue cut Germany down with a 2-1 victory that threw the doors of Group E wide open.

Portugal's Cristiano Ronaldo became the first man to score at five World Cups by netting a penalty in a 3-2 win over Ghana at the shipping container 974 Stadium. Brazil eased into the tournament by beating Serbia, only to lose Neymar to injury.

But the unpredictability continued.

PHOTO: REUTERS

Iran scored in the eighth and 11th minutes of stoppage time as they recovered from their drubbing by England to beat Wales 2-0 in a game in which Wales keeper Wayne Hennessey was sent off, one of only two red cards in the group stage.

Like Iran, Costa Rica also showed incredible bouncebackability as they edged Japan 1-0 to set up what was to be a stomach-churning climax to Group E.

And the shocks kept coming.

MAGNIFICENT MOROCCO

Belgium, the world's second-ranked team, were humbled 2-0 in Group F by a magnificent Morocco, whose fans turned Doha red in celebration. Morocco went on to reach the knockout phase for the first time since 1986, while Belgium are back home.

The simultaneous final group matches ratcheted the tension off the scale.

Tunisia thought they had given themselves a shot at reaching the last 16 with a symbolic win over France but their joy turned to tears as Australia stunned Denmark.

Argentina completed their recovery from their Saudi shock to outclass Poland in a gripping conclusion to Group C. Poland also went through on goal difference, although at one point all that separated them from Mexico - who were desperately trying to rack up goals against Saudi Arabia - were yellow cards.

If that was exciting, what happened the following night almost threw the football world of its axis.

Spain, serene in their first two games, led against Japan at the Khalifa Stadium and appeared set to clinch top spot in Group E, while across town Germany were beating Costa Rica and also looked on course to qualify. Then everything went crazy.

Goals by Itsu Doan and Ao Tanaka gave Japan the lead and Costa Rica hit back to lead Germany. For four minutes, both Spain and Germany were heading for the exit door.

Germany ended up saving Spain's bacon by winning 4-2 but not their own as Japan hung on to take their place in the last 16. They were joined 24 hours later by South Korea after Hwang Hee-chan's added time goal beat Portugal 2-1, although South Korea's players had an excruciating wait in the centre circle praying that Uruguay would not score again against Ghana.

Even then the group stage chaos was not done, as Cameroon signed off with a 1-0 victory over already-qualified Brazil - statistically the 12th shock of the tournament - and goalscorer Vincent Aboubakar was promptly sent off for over-celebrating.

After probably the most memorable group phase of any World Cup, now for the serious business. But please don't stop the fun.