Spain goalkeeper David de Gea believes his side are facing a tough test against Belgium and highlighted Eden Hazard and Christian Benteke as quality opponents.
Fresh from defeating England 2-0 in Alicante, the European champions continue their preparations for Euro 2016 with a friendly in Brussels against the team ranked number one in the world.
De Gea is in no doubt that Spain will have to be at their best to continue their fine recent form and make it eight consecutive victories.
"If they are at number one then there must be a reason for that," he said.
"They have a very strong team with great individuals. They have qualified for the Euros playing well and have only lost one game in the qualifiers.
"Hazard, Benteke - they are very strong players. It will be a great test for us to face Belgium, especially when they are playing at home."
De Gea is expected to get his chance to play in goal after Iker Casillas was preferred against England and he feels Vicente del Bosque's rotation system is working well.
He said: "It is the decision of the coach and he tries to give minutes to every player.
"It is good to play with the national team and get game time. There are many players, so it is difficult to manage minutes for everyone."
Hosts Belgium have won five matches in a row since they suffered defeat to Wales back in June.