Belgium goalkeeper Thibaut Courtois said his side were outplayed in every way in a 2-0 defeat to Italy in their European Championship opener on Monday.
Despite facing the four-time World Cup champions, Belgium's "golden generation" were favoured in the Group E clash in Lyon, but goals from Emanuele Giaccherini and Graziano Pelle allowed Italy to take all three points.
Courtois made a number of fine saves in the losing effort, but he said Belgium needed to do much better in the games ahead.
"We were outclassed on all fronts," said Courtois, as quoted by Sportwereld. "Tactically, technically and organisationally we came up short.
"We made the same mistakes as in the friendly games. For the first we did not follow our man."
Belgium next face Republic of Ireland on Saturday, followed by Sweden on the following Wednesday.
"This is a big disappointment, because the first match is very important," Courtois said. "We could have done a great thing after the draw in the other match.
"The next two games we should be winning. We have to play better."
Belgium defender Jan Vertonghen was similarly let down by his team's performance, though he saw some promising signs.
"This is a disappointing result. However, we did not play badly," he said.
"We knew how Italy were going to play and anticipated their moves. They only really had one chance and it was enough.
"We should not despair after this, as I am disappointed with the result, but not the performance. Today we showed we are a good team."