The 19-year-old Barcelona centre-half has excelled in defence for La Roja at this summer's tournament, having played in all seven matches so far under Luis de La Fuente.
Now, Cubarsí believes that Spain have quietened the doubters once and for all after last night's historic victory.
Speaking after the match, Cubarsí said: “There was some talk about the defence and the goalkeeping on our side, but we have shut a lot of mouths”.
“I think that one of the most important things in football now is to keep a clean sheet”.
The defender posted a 7.4 Flashscore rating against France as he completed the full 90 minutes, winning 100% of his tackles with a 91% passing accuracy.
Now, Cubarsí and Spain await the result of the mouth-watering semi-final between Argentina and England tonight, and will undoubtedly look to put the defensive clamps on once again in the World Cup final on Sunday.