"Our squad is on a cloud right now and the players have every right to be positive about our form going into the quarter-finals, and about our chances of going much further in this tournament," Kompany wrote on the BBC website.
The Manchester City captain, who missed the tournament with a thigh injury, however acknowledged that Wales beat the Belgians 1-0 in Cardiff and drew in Brussels in qualifying.
"The Wales team will not need to watch a lot of videos before the game, because they know us so well - and we know them so well too," Kompany added.
"Our games in qualifiers were very close and the last team to make a mistake was us, so you learn from your mistakes.
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"In that sense I think and I hope it is advantage to us this time."
(Reporting by Ian Rodricks in Bengaluru; Editing by Greg Stutchbury)
