Reason: Extraordinary talents of ordinary man
Argentina might have Lionel Messi but it is Germany's scoring juggernaut who poses the greatest threat tomorrow morning.
How do you stop a ghost? Argentina have only conceded three goals in six matches, but they have not had to contend with anyone like Thomas Muller.
The German, who looks like a nobody, has suddenly drifted in behind the right back and you find yourself a goal down without quite knowing how it happened.
Muller is a most singular man.
The great strikers of history, from Eusebio to Pele to Maradona, have always threatened. They are a constant menace. Defenders cannot take their eyes off them. But Muller is just too ordinary to gain anyone's attention.
He doesn't run, he shambles. Muller looks like a teenager who is still growing into his legs. His limbs flap about in the wind. His socks are halfway down to the ankles.
You can half imagine him ambling up a German lane, a schweinsteiger in his hand, driving a mob of pigs.
Or he is the boy from down the road, never quite part of the gang, who always arrives with a ball wanting to join in. All right, you say.
But then he doesn't get a penalty, and lies on the ground screaming and waving his legs in the air with the frustration of a toddler, before taking his ball and going home again.
After Muller made his debut against Argentina in 2010, Diego Maradona refused to share a post match conference with the young German, and sniffily said, "He looks like a ball-boy."
After Muller scored a hattrick against Portugal at the start of this World Cup, Maradona said, "He has no muscles but he played well."
The fact that Muller just doesn't look or move like a footballer is part of his threat and you wonder if Maradona's disdain will be shoved back at him tomorrow.
Somehow Argentina, who have only conceded three goals at this World Cup, have to prevent Muller from opening them up.
When I watch Kiwi kids play soccer, I see a lot of teenagers with good ball skills, but very, very few with game sense. They do not see space.
The game is not part of the culture. On a rugby pitch no country is better at finding gaps. But even the best New Zealand footballers rarely manipulate space.
So watch Thomas Muller. He is known as the "raumdeuter."
That translates as space investigator or interpreter. I prefer space invader given the way that Muller's limbs seem to veer to the horizontal.
Muller took Brazil apart. Marcelo, rated as one of the best left backs in the world, is probably sitting at a café right now, looking over his shoulder to see if Muller is still there.
The German is a drifter. How he made up for missing the semi-final against Spain four years ago.
The opening goal against Brazil was castigated as bad marking by the commentators, but it wasn't.
David Luiz was picking up Muller on the near post. Suddenly the German spun through an arc and when Luiz went to follow he found his path blocked off by Klose. Luiz fought to get through, but by then it was too late and Muller, no need for extravagance, was side-footing a volley into the net.
The second goal was all Muller. He started the attack, he took the throw-in, he got the ball back and then slid a ball into the centre that had Fernandinho over-reaching.
A moment after he had played the pass, just long enough for Gustavo to switch off, Muller made his run from the touch-line into the middle of the area. His one touch lay-off to Klose was sublimely simple and the German striker scored at the second attempt.
Manager Joachim Low, who curiously looks steeped in a dye extracted from bats' wings, says, "He has instinct for creating dangerous situations where you don't expect it. Thomas is a very unorthodox player; sometimes you don't really know or cannot predict his pathways on the pitch. He is difficult to interpret for opponents, but he has one aim - how can I score a goal? That is his only focus and is what makes him so dangerous."
That doesn't fully do him justice. Muller is a born scorer and creator. Louis van Gaaal said when he was Bayern's manager, "With me Muller always plays." And when Muller plays, others play.
Germany's seventh goal against Brazil was such a wonderfully extravagant finish by Andre Schurrle, that observers were distracted from Muller's contribution.
Having moved from the right to an unorthodox centre forward, Muller had run behind the defence on to a throw-in.
Seemingly pinned in the corner, he swivelled and, first touch, clipped a perfect ball into Schurrle's path. It was one of the beautiful moments of this Cup.
Perhaps just as importantly for his team, Muller wins them respite. Brazil committed eleven fouls against Germany and one yellow card. Six of the fouls and the yellow card were goaded by Muller.
Luiz was so frustrated at one point that he took a great swipe at the space invader.
In the past, says Muller, German football "was all about running and fighting."
Now it is about running and passing.
If Argentina are to beat the best team at this Cup, then Rojo and Mascherano will need to smother the ghost. Muller's first touch is not always in the class of Lionel Messi's, but his movement is second to none.
He has a chance of becoming the first man to win the Golden Boot for a second time, and yet that hardly matters compared to the big goal of winning Germany's first World Cup since 1990.
AT A GLANCE
TEAM OF THE WORLD CUP: Manuel Neuer; Philipp Lahm, Thiago Silva, Mats Hummels, Ricardo Rodriguez; Javier Mascherano, Andrea Pirlo; Arjen Robben, James Rodriguez, Lionel Messi; Thomas Muller.
Sunday Star Times