Vinicius, 25, immediately flagged a comment made by Prestianni to referee Francois Letexier after he opened the scoring last week.
Prestianni was accused of racially abusing Vinicius Junior after he covered his face with his shirt which led to the game being stopped for over 10 minutes.
The Benfica star could face a 10‑match ban if found guilty and the club claimed that he was not guilty as they appealed the decision to suspend him.
However, UEFA have opted to keep Prestianni, who denies the allegation, provisionally suspended:
“The appeal lodged by SL Benfica is dismissed. Consequently, the UEFA Control, Ethics and Disciplinary Body’s decision of 23 February 2026 is confirmed.
"Mr. Gianluca Prestianni remains provisionally suspended for the next UEFA club competition match for which he would otherwise be eligible.”
Prestianni denied the allegation last week with a statement of his own
He wrote: “I want to clarify that at no time did I direct racist insults to Vini Jr, who regrettably misunderstood what he thought he heard.
“I was never racist with anyone and I regret the threats I received from Real Madrid players.”
Prestianni, 20, will not feature at the Bernabeu this week as the two sides clash once more in a fight for a spot in the next round.