Real Madrid have launched an investigation after a supporter allegedly performed a Nazi salute before the club's Champions League win against Benfica on Wednesday.

Prior to the kick-off at the Bernabeu, a fan appeared to make the fascist gesture as the television cameras panned around the 83,000-seater stadium.

The fan was identified by security staff moments later and ejected from the ground.

Real beat Portuguese side Benfica 2-1 in the second leg of their knockout round play-off tie to progress 3-1 on aggregate to the last 16 of the Champions League.

In a statement, the Spanish club said they have asked its disciplinary committee "to initiate an immediate expulsion procedure" for the fan.

"Real Madrid condemns this type of gesture and expression that incites violence and hatred in sports and society," it added.

The incident comes after Real Madrid forward Vinicius Jr alleged he was racially abused by Benfica's Gianluca Prestianni during the first leg in Lisbon.

The 25-year-old Brazilian, who scored the only goal of the game, informed the referee he had been racially abused by Prestianni and the game was halted for 10 minutes after he and his Madrid team-mates left the pitch.

Argentine winger Prestianni was subsequently handed a provisional one-match ban and missed the second leg after Uefa rejected Benfica's appeal against his suspension. He could still face further punishment, pending the result of a full Uefa investigation.

Vinicius, who scored Madrid's winner on 80 minutes, received support by the home fans as a banner with the words "no to racism" in Spanish was displayed in the stands before kick-off.

His team-mate Aurelien Tchouameni also said the win was "for everyone who stands against racism".