Santos, 57, was keen to highlight that the group is wide open with his side having every chance to progress to the quarter-finals at Euro 2012.

"There are no favourites. The Czech Republic and Russia might be strong teams, while Poland are co-hosts, but it's still the most open group of them all," Santos said.

"Every team has a 25 percent chance of advancing to the next stage," he said at a press conference on Wednesday.

"What will be important is that we use this time before the competition to improve on our ball possession.

"It's a key aspect for a successful campaign at the Euro finals. In our group it could turn out to be the decisive factor.

"The team that will force their opponents to run and chase the ball will have greater chances of success."

Santos also stressed the importance of Thursday's friendly against Armenia.

"We'll try to experiment with some of our plans. I want to see whether specific players can be trusted with specific roles," he said.

"What we want from these preparations is to improve ourselves as a team. What we have already succeeded in is creating a friendly team atmosphere.

"We want to continue playing in high level in defence, but we also need to improve ourselves in attack," he said.

Greece open their Euro 2012 campaign against Poland on June 8.