BELGIUM 2-1 UNITED STATES
It was one of the great rearguard actions of the World Cup. Belgium's quest for a goal lasted 93 minutes and the United States defended defiantly. The sheer volume of clearances made by Jurgen Klinsmann's team -- and centre-backs Omar Gonzalez and Matt Besler in particular -- was testament to their organisation and spirit, but also indicates the amount of pressure they were under.
The United States actually have quite a high defensive line; indeed, some of Belgium's chances came from Divock Origi and his replacement Romelu Lukaku running in behind it. But a pitch map of the Americans' 70 clearances shows how many were made from an area between 6 and 18 yards from their goal (and it is also worth remembering Tim Howard is a goalkeeper who comes off his line to claim crosses, so it could have been even more). That was how far back they were forced.
It is significant that many of the red blobs are in the centre and left of the American defence, which indicates how often the ball was coming in from the opposite flank, Belgium's left. This was the key battleground for much of the game, a contest with distinct similarities for the two sides. Both full-backs raided forward; both were troubled defensively because their winger didn't track back. DeAndre Yedlin imitated Fabian Johnson when the United States' first-choice right-back went off with an injury, while Jan Vertonghen cemented his reputation as one of the foremost attacking left-backs in the competition.
Vertonghen had Eden Hazard stationed in front of him and he isn't expected to defend. The USA's problem was that Graham Zusi failed to assist Yedlin and gave Vertonghen free rein of the flank. As 4-2-3-1 played 4-2-3-1, it meant he -- and one centre-back -- were in effect the spare men for Belgium when they were in possession.
The Tottenham player had 98 touches, the most of anyone on the pitch, and the majority were in the American half. Yet the same is true of Yedlin, too, who was on the ball more in Belgian territory. He had difficulties, however, when Kevin de Bruyne and Hazard swapped positions for extra time and the Wolfsburg man, advancing into vacant space on the American right, set up Lukaku for the second goal.
ARGENTINA 1-0 SWITZERLAND
Angel Di Maria's eventful day ended when he scored the winner. By then he was playing as the right winger in a 4-2-4 formation. He began on the left in 4-4-2, a sign of the many changes Argentina made in their search for a breakthrough.
Di Maria was relocated in virtually every one of manager Alejandro Sabella's rethinks: he swapped with Ezequiel Lavezzi to go on the right in 4-4-2. Then, when the Paris Saint-Germain man joined the forward line in a 4-3-1-2, Di Maria was on the left of the midfield trio. He then became the right winger in 4-2-1-3 before eventually Lionel Messi joined Di Maria, Gonzalo Higuain and Rodrigo Palacio to form a quartet in attack.
The problem was that, despite the many formations, Argentina's tactics seemed two-dimensional: either they gave the ball to Messi or they crossed. Argentina delivered 52 crosses, the most in this World Cup. Di Maria was responsible for 19 of them, finding a teammate only four times. A map of where his crosses came from highlights that he spent similar amounts of time on either flank.
Argentina's wing play was notable, too, because for most of the match, their most effective attacker on the sides was left-back Marcos Rojo. Their full-backs had received too little protection against Nigeria, when Pablo Zabaleta was troubled by Ahmed Musa, and Lavezzi began stationed in front of him.
Yet when they moved to 4-3-1-2 and 4-2-1-3, Rojo relished the space in front of him, overlapping effectively and forcing a Swiss substitution as, with right-back Stephan Lichtsteiner exposed, Granit Xhaka was replaced by Gelson Fernandes. Switzerland had concentrated on the centre of the pitch, looking to crowd out Messi -- something Gokhan Inler and Valon Behrami did particularly doggedly -- until Rojo stretched the game.
FRANCE 2-0 NIGERIA
Mathieu Valbuena helped create both of France's goals, taking the corner for Paul Pogba's opener and sending in the low cross for Joseph Yobo's own goal. France's most creative player was also their busiest. He had 86 touches, more than anyone else.
It is rare a forward or attacking midfielder has that distinction. A scatter chart of Valbuena's touches shows his role in the side. France play a variant of 4-3-3 that doesn't have genuine natural width, apart from the full-backs: Valbuena is more of a No. 10 while his left-sided counterpart, Karim Benzema, was a striker who flourished when moved infield after Olivier Giroud was substituted.
Valbuena spends some time near the touchline, but often vacates that area for the overlapping Mathieu Debuchy; as his immediate opponent was Ahmed Musa, who had excelled on Nigeria's left wing against Pablo Zabaleta in Nigeria's previous game, it was a risky move.
Where Valbuena likes to play, however, is between the lines. His ability to find space in the inside-right position, eluding Nigeria's defensive midfielders, led to Benzema having a shot cleared off the line. On the comparatively few times he took up an outside-right position -- apart from taking corners -- he illustrated his crossing ability, with both the ball when Paul Pogba had a first-half volley saved and the centre for France's injury-time goal.
The difficulty for any opponent facing France lies in the question of who picks up Valbuena: he roams between a full-back, a wide midfielder and a central midfielder's sphere of influence. The other problem for defensive midfielders is that Didier Deschamps uses two box-to-box runners, in Pogba and Blaise Matuidi, who make lateral runs. They utilise power, while Valbuena has more delicacy, and Nigeria's case was hindered when they lost Ogenyi Onazi, the left-sided holding midfielder, to injury. Valbuena found more space thereafter.
ALGERIA 1-2 GERMANY
Manuel Neuer almost redefined the nature of goalkeeping. If the notion of a sweeper-keeper is not new, it is rarely as pronounced. The German goalkeeper was his side's most reliable defender. His scatter chart indicates how many times he came out of his penalty area, and that some were up to 20 yards outside it. Of his 59 touches, 21 came outside the 18-yard box; both statistics, unsurprisingly, were the most of any goalkeeper at this World Cup.
Germany's was a needlessly risky strategy -- Neuer was one mistimed tackle or misplaced clearance away from a goal or a red card -- and it was one that was created by a perfect storm. Germany had a high defensive line, poor organisation at the back, a slow centre-back in Per Mertesacker, and they faced a quick, counterattacking Algeria team.
Germany's group games, particularly against Ghana, illustrated that quick forwards can catch them on the break. The strange element was that Germany adopted even higher starting positions -- there were times when both centre-backs were in the Algeria half -- and it almost cost them. Algeria had the ideal striker, with the fast Islam Slimani, to run into the space behind them.
Germany struggled in particular on the right half of the back four, where the rookie Shkodran Mustafi and the one-paced Mertesacker were paired, partly because Slimani spent more time there, and they also had issues with both full-backs. Their back four are all central defenders by trade and their full-backs, unlike counterparts at some other countries, don't bomb on all the time. Nevertheless, Algeria used the pace of El Arabi Soudani and Sofiane Feghouli to exploit the positional uncertainty of Mustafi and Benedikt Howedes respectively. It is notable from Neuer's touch map that he had to make diagonal runs out of his penalty area to cover for the full-backs.