Cesc Fabregas tops WhoScored's list of debuts from the weekend but you might also be surprised to see Patrick van Aanholt and Andrew Robertson in there...
We could have done practically a whole quiz on Chelsea's loanees but instead we've gone for the traditional one question per club...
Argentina v Bosnia & Herzegovina (June 15 11pm BST)
It's a late kick-off for UK viewers but it's also the first chance to see how Argentina are shaping up. Incredibly, they haven't reached the last four since England did so in 1990 but they lifted the trophy the last time the tournament took place in South America and with Lionel Messi and Sergio Aguero, you'd have to think they have a good chance of going far. Even if they don't, it should be an entertaining watch as coach Alejandro Sabella is expected to play the star duo off a third forward in Gonzalo Higuain with Angel Di Maria fizzing behind in midfield.
If there's a weakness in the Argentina team it's in the back line and that's what makes World Cup first-timers Bosnia and Herzegovina such cracking opponents to draw in their opening game. Coach Safet Susic has said in the past that his team only know one way to play and with Miralem Pjanic feeding Edin Dzeko, you'd expect them to fashion chances of their own. Even if Susic isn't willing to trade blows, it'll be fascinating to see if he goes through with a mooted ploy to man-mark Messi with Muhamed Besic. If successful, it could be a move that shapes the whole tournament.
Switzerland v France (June 20 8pm BST)
"In Switzerland, they had brotherly love, they had 500 years of democracy and peace - and what did that produce? The cuckoo clock." The famous Harry Lime quote from 1949 classic The Third Man hints at the stereotype of Swiss football - solid enough but nothing to get too excited about. To illustrate the point, in the last two World Cups, Switzerland have conceded just one goal in seven games and still failed to get past the first knock-out stage. This time, things are different.
Ottmar Hitzfeld has a wealth of young talent at his disposal - benefiting from Switzerland's superb record in under-age competitions - and is expected to name a starting line-up that will see half of the outfield players under the age of 23. Granit Xhaka, Xherdan Shakiri and Josip Drmic are young attacking prospects who'll get their chance to shine and the second group game against France promises to be the pick of the match-ups in Group E.
France have a point to prove after the well-documented shambles that was their brief visit to South Africa four years ago and a slip-up here could precipitate problems for Didier Deschamps. If there is an encouragement for the group favourites it's that Switzerland's weak area is in the heart of their defence. An issue for Hitzfeld but good news for the neutral - this one could see goals.
Holland v Chile (June 23 5pm BST)
Louis van Gaal has talked of tweaking his formation but whatever Holland team lines up against Chile, it's sure to be an attacking and exciting one. Nigel de Jong survives from the more robust outfit of four years ago but Marc van Bommel is long gone and with Wesley Sneijder earning praise from Van Gaal for his fitness levels, it wouldn't be a huge shock to see a three-man midfield that includes just one defensively minded midfielder. That's a lot of creativity in support of a forward line that will include Arjen Robben and Robin van Persie.
They say styles make fights and that would certainly be the case against Chile. Jorge Sampaoli has restored the whirling dervish mentality of the Marcelo Bielsa regime and that means pressing and passing at a giddy tempo with seemingly reckless abandon. The Chileans have playmakers of their own too and the brilliant Jorge Valdivia can certainly be a joy to watch but the real intrigue will be whether the more athletic South Americans can make the Dutch look lethargic. And there's plenty on this one - with Spain also in Group B, the losers are likely to be on their way home.
Japan v Colombia (June 24 9pm BST)
Colombia have been earmarked as a team to watch in Brazil for some time now with Jose Pekerman forging a talented team of excited youngsters, grizzled veterans and players at the peak of their powers. It's their first World Cup in 16 years but some bookies have them among the six favourites to win the whole thing. We'll have a clearer idea of the merits of that claim by the time of their final game of the opening stages but with no obvious whipping boys in Group C, the clash in Cuiaba against Japan will surely have something on it. It could well be a little cracker too.
Japan have never made the quarter-finals but there are sage judges willing to argue this vintage can change that. Alberto Zaccheroni has a history of producing tactically interesting teams and while his favoured 3-4-3 has been abandoned in favour of a more familiar 4-2-3-1, the Italian has got the Blue Samurai playing a high-tempo game that's easy on the eye. If there's a flaw to his team it's in a back-line prone to lapses and with Pekerman able to boast a plethora of attacking talent - with or without Radamel Falcao - that could spell goals. This one will also have round-of-16 implications for England if Roy Hodgson's team qualify earlier in the day so it's well worth a watch.
USA v Germany (June 26 5pm BST)
Germany's reputation as relentless if unspectacular winners will take some shaking after lifting the World Cup three times and becoming the first team to win the European Championship on three occasions, but perceptions within the country are changing. Germany haven't won a trophy in 18 years despite a series of near misses, but they have earned the tag of entertainers. Much of that stems from Jurgen Klinsmann's time in charge of the national team when he introduced a faster tempo to the German game that carried them to the semi-finals of the 2006 home World Cup.
Klinsmann now finds himself in charge of the United States and he's continuing to shake things up. The omission of Landon Donovan shocked the public, but the iconic star had lost some of his pace and was no longer an obvious fit for the brand of exuberant high-pressure football that the coach demands of his players. An afternoon kick-off in the heat of Recife might not be conducive to that approach but it could also offer the tantalising prospect of an upset. With Ghana and Portugal making up Group G, this one could be tight - What price Klinsmann eliminating the Germans?
Adam Bate - follow him on Twitter as he dies a slow 'lads holiday' death in Spain