Eden Hazard is a doubt for Belgium's friendly with Spain, whose centre-back Marc Bartra is expecting the European Champions to be sternly tested by the world's number one ranked team in Brussels on Tuesday.
Chelsea attacking midfielder Hazard did not train for Belgium on Sunday because of illness, while striker Laurent Depoitre was also missing from the session with an ankle injury.
Belgium go into the match unbeaten in five games, having produced a fine demonstration of their quality on Friday with a 3-1 defeat of Euro 2012 finalists Italy.
Italy took the lead through an Antonio Candreva goal in the third minute, but Jan Vertonghen, Kevin De Bruyne and Michy Batshuayi hit back to secure victory for Marc Wilmots' men.
And Belgium, who reached the quarter-finals of the World Cup last year, will aim to lay down another marker ahead of the Euro 2016 finals by seeing off Spain at the Stade Roi Baudouin.
The gane represents the first meeting between Belgium and Spain since 2009, when the Iberian side eased to a 5-0 win.
Belgium's fortunes have changed dramatically since then and their resurgence and recent run of form should give the hosts reason for confidence as they attempt to beat Spain for the first time since the 1986 World Cup.
That win came on penalties in the quarter-finals and you have to go back to the 1980 European Championship for the last time Belgium overcame Spain in normal time, doing so with a 2-1 win in the group stages.
Spain should be in high spirits as they attempt to extend their dominance over Belgium after cruising to a 2-0 win over England last time out, a game in which Thiago Alcantara was forced off in the first half with a knee injury.
Bayern Munich playmaker Thiago will be on the sidelines for a few weeks due to the problem.
Mario Gaspar's spectacular acrobatic volley opened the scoring for Vicente del Bosque's men before Santi Cazorla made sure of the victory six minutes from time.
Despite the routine nature of the win, Barcelona defender Bartra is not getting complacent ahead of the contest in the Belgian capital.
He said: "They [Belgium] have great players in big leagues and we're going there to win, but we know it will be difficult."
Celta Vigo forward Nolito echoed Bartra's sentiments, but is relishing taking on one of the emerging powers in European football.
Nolito said: "It's one of those matches that you like to play no matter what, like the one against England and of course I would love to be there. It will be tough and I am sure it will be nice."