One match is a small sample size, but the opener of the 2014 World Cup helped reinforce what were some of the biggest concerns surrounding Brazil and Croatia heading into the tournament.
The Brazilians saved face and walked away with a 3-1 win in Sao Paulo on Thursday night, but it didn't come easy. The Croatians opened the scoring but took their foot off the gas shortly thereafter, allowing their opponents to get back in the match.
Brazil should also count themselves lucky for the penalty that gave them the lead and all but sealed the victory.
Both of these teams should advance to the knockout stages, but sooner or later, they'll have to address these main issues.
Brazil: The Tactical Anarchy of Dani Alves
When going forward, Dani Alves is one of the best full-backs in the world. It's the whole defending thing that he can sometimes mess up.
At Barcelona, Alves usually has Sergio Busquets, Gerard Pique and Javier Mascherano covering for his attacking runs. They ensure that the right side of defense doesn't become too exposed. And having played together for so long, everybody knows what they're doing on the pitch.
The Brazilian national team hasn't been able to build the kind of understanding and continuity necessary for the players to instinctively understand where they need to be if the Barca defender is bombing forward. As a result, you get a game like Thursday night's, when 34-year-old Ivica Olic managed to get acres of space down the left flank.
On Croatia's goal, TSN's Jason deVos did a great job of showing how Alves' forward run left Thiago Silva and David Luiz scrambling:
When the Barcelona star was younger, he had the stamina and speed to quickly recover. He could afford to play as a glorified attacker.
Even though his body won't allow him to do the same things he could a few years ago, Alves remains stuck in his attack-first mindset. Liverpool Offside made the parallel to Glen Johnson, who, while not up to the quality of the Brazilian, is suffering from the same problem:
Luiz Felipe Scolari will find it difficult to rein in Alves' forward runs. He's played one way his entire career, so he's unlikely to change it all of a sudden.
As a result, the coach might have to tweak his tactics so as not to get carved open again at the back. DeVos proposed using three centre-backs and two defensive midfielders:
That would be a bold plan, but as we saw on Thursday night, something needs to change defensively.
Croatia: Shore Up the Back Line
Defense was Croatia's most notable flaw coming into the World Cup, and you saw exactly why on Thursday.
You can put aside the penalty on Dejan Lovren. Even the most passionate Brazil supporter has to admit that there was very little contact between the centre-back and Fred before the Fluminense forward dramatically fell to the turf.
"If that was penalty, than we should play basketball, not football!" Croatia coach Niko Kovac said in an interview with Croatian state television network HTV, via Goal's Andrew Wychrij. "It was a shame! The referee had different set of rules for us and different for Brazil. Shameful refereeing for [the] World Cup!"
Looking back on the match, though, Kovac should look at the performance of Stipe Pletikosa as one of the biggest reasons for his team's loss. Pletikosa arguably should've saved Neymar's penalty and then had his feet stuck in cement for Oscar's goal that made it 3-1.
ESPN's Alexi Lalas was particularly harsh on the goalkeeper after the match:
Kovac can't do much to tactically improve his goalkeeper, so all he can do is ensure that his centre-backs are closing down on attackers quicker so as to limit the opposition's shots on target. Maybe that also means adding a defensive midfielder and sacrificing one of Ivan Rakitic or Mateo Kovacic.
Croatia should have a slightly easier time against both Cameroon and Mexico, but their leaky defense may be their ultimate undoing if something doesn't improve.