Luckily for countries that have suffered poor opening results, we aren't yet to the knockout stages of Euro 2012. 

It's not easy, but even with just three group-stage matches, it is completely possible to turn around a negative result and still make a deep run in the tournament.

Just look at Spain in the 2010 World Cup.

The Spaniards lost their opening match to Switzerland, but still managed to return to form and go on to become champions of the world. 

Let's take a look at what countries must improve on their opening matches if they want to make a similar run this year. 

Netherlands (Lost 1-0 to Denmark in Opener)

If you're in a group with Portugal and Germany, two of the top teams in the world, you can't afford to lose against Denmark.

And that's exactly what the Dutch did.. 

If the Dutch lose to the Germans on Wednesday, they have essentially no chance of making it to the knockout stages. If they want any chance of competing with Germany, plenty of players will have to be better than they were against the Danes. 

Robin van Persie, for one, was no where near his Arsenal form. He blew plenty of goal-scoring opportunities. Going forward, he's going to have take advantage when he gets the chance. 

Additionally, Arjen Robben needs to start looking for his teammates. His tunnel vision was bordering on atrocious against Denmark. 

Portugal (Lost 1-0 to Germany in Opener)

Who would have thought before the tournament started that both Portugal and Holland would be in danger of missing the knockout stage?

Portugal lost to Germany in their opening match. They now badly need a win against Denmark, who are in a good position with three points.

Due to the Danes' unexpected early victory, they will likely sit back and attempt to avoid a loss, making things tough for Portugal's inconsistent offense. 

If Portugal only gets a draw against the Danes, they will likely need to beat the Netherlands and get some help from Germany in the group's final match. Cristiano Ronaldo will have to get some help from his teammates if the Portuguese want to find themselves in a comfortable situation.

Croatia (Beat Ireland 3-1 in Opener)

Yes, the Croatians won their opening match against Ireland, but they still have some work to do. 

Croatia got some help from Shay Given's head, but they won't be so lucky against Spain or Italy
Christof Koepsel/Getty Images

All three of the goals were a result of Ireland's porous defense, while the defense also looked susceptible late in the match.

Against Spain and Italy, who drew 1-1 and will likely both get big results against the Irish, Croatia must be better. 

Luka Modric must continue to be his brilliant self, Mario Mandzukic needs to keep being a force in the air and the back line must improve. Even a draw against both Spain and Italy, which will be incredibly hard to achieve, might not be enough to advance.

Croatia needs to be brilliant in its next two matches.

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