They say that the hardest thing is not to reach the summit, but to stay there. The fact that only two teams have managed to retain the FIFA World Cup™ shows that the adage certainly holds true in this competition. Just ask Germany who, after claiming the Trophy in such impressive fashion at Brazil 2014, were brought back down to earth with a bump in their Russia 2018 opener. In the process, Die Mannschaft joined Italy (1950), Argentina (1982 and 1990), France (2002) and Spain (2014) on the list of world champions to have kicked off their title defence with a loss.

A lightning counter-attack finished off by Mexico's Hirving Lozano defeated Joachim Low's side, who will have to tighten up defensively before taking on Sweden or else they could face an early exit. Everything clicked perfectly for El Tri, who held firm at the back and capitalised on the Germans' frailties to constantly threaten on the counter-attack. "We set out to catch them on the break using two wingers, including Hirving, who is our fastest player," Mexico coach Juan Carlos Osorio said after the match.

Brazil, another of the big favourites for the crown, did not learn from Germany's lesson and were frustrated by Switzerland. Trailing to Philippe Coutinho's superb curling effort, Die Natihit back through Steven Zuber's header to repeat the feat of 1950, when the Swiss held the Brazilians to a 2-2 draw in the countries' only other meeting at the competition.

Coutinho's strike was a beauty, but Aleksandar Kolarov's free-kick winner for Serbia against Costa Rica was no less so. Los Ticos were one of the sensations of the 2014 tournament, enjoying a dream run to the quarter-finals before being beaten on penalties by the Netherlands, but they too realised that past exploits count for nothing. Kolarov's stunner not only earned the Orlovi three points: it will have also gone a long way towards healing Serbia wounds from their only previous campaign at the global extravaganza, in 2010, when they finished bottom of their group.

When he was brought off the bench to help Mexico see out the game against Germany, Rafael Marquez became just the third player ever to feature at five different World Cups. The other two are Marquez's compatriot Antonio Carbajal (1950, 1954, 1958, 1962, 1966) and, curiously enough, a German: Lothar Matthaus (1982, 1986, 1990, 1994, 1998).