Benfica claim there is a "defamation campaign" against Gianluca Prestianni after Uefa launched an investigation into claims he racially abused Real Madrid winger Vinicius Jr.

Tuesday's Champions League tie at Benfica was halted for 10 minutes after Vinicius reported alleged racist abuse to referee Francois Letexier and he and his team-mates left the field.

Brazil international Vinicius, who has been a victim of numerous incidents of racist abuse during his playing career, later said in a post on Instagram: "Racists are, above all, cowards."

Prestianni, who could face a minimum 10-match ban from European competition if found guilty, denied directing racial abuse at Vinicius.

On Wednesday, Benfica defended Prestianni via a post on their official X account, alongside a video of the alleged incident, saying: "Given the distance, the Real Madrid players could not have heard what they claim to have heard."

The club added they "fully support" and believe the version of events presented by Prestianni.

"[Prestianni's] conduct in the service of the club has always been guided by respect for opponents, institutions and the principles that define Benfica's identity," Benfica added.

"The club regrets the defamation campaign of which the player has been a victim."

Benfica manager Jose Mourinho said in his post-match interview that he had been told different things by Vinicius and Prestianni regarding the incident.

Mourinho, who managed Real for 178 games between 2010 and 2013, said Vinicius had been disrespectful in his goal celebration and pointed to their legendary striker Eusebio as proof that Benfica is not a racist club.

"The club reaffirms, clearly and unequivocally, its historical and unwavering commitment to defending the values of equality, respect and inclusion, which are in line with the core values of its foundation and have Eusebio as their greatest symbol," Benfica said.

Mourinho's and Benfica's comments have been criticised by a number of people, including anti-discrimination charity Kick It Out.

Kick It Out chair Sanjay Bhandari said both the club and manager had "failed".

"It's a natural inclination to want to believe your player, but the reality is they didn't hear it," Bhandari told BBC Sport.

"There's only two people who are in that conversation and two people who could have heard what was said.

"I think the better reaction from a club with Benfica's fantastic stature would be to say we're going to cooperate with the investigation.

"This is quite typical after these kinds of discriminatory events. The discrimination is one thing, the gaslighting is another."

Fifa president Gianni Infantino said he was "shocked and saddened" by the incident and commended Letexier for activating the anti-racism protocol.

"There is absolutely no room for racism in our sport and in society - we need all the relevant stakeholders to take action and hold those responsible to account," he added.

"I will always continue to reiterate: No to racism, no to any form of discrimination!"