Sevilla condemned a Rayo Vallecano fan's "obscene" act early Tuesday after the supporter poked forward Lucas Ocampos's backside with his finger during a La Liga match.

Ocampos was taking a throw-in during Sevilla's 2-1 win at Rayo on Monday when the fan reached out and prodded the Argentine between the buttocks.

"Our player Lucas Ocampos suffered an obscene and totally inappropriate action by a home fan," wrote Sevilla in a statement.

"Sevilla hope the opportune measures are taken so behaviour like this is not repeated at a football stadium."

Ocampos turned to look at the fan and then called over referee Francisco Hernandez Maeso.

"Sevilla gives their maximum support to Lucas Ocampos, who demonstrated his poise and enormous professionalism, despite the unacceptable attitude of the fan who accosted him," added the club.

Ocampos said he hoped the incident would be taken seriously by Spain's football authorities.

"I hope La Liga takes it seriously, like it takes racism and these things," Ocampos told DAZN.

"I don't think all Rayo fans are like this ... but there's always an idiot.

"I hope it doesn't happen elsewhere, because if it happened in women's football, we know what could happen -- I held back, because I have two daughters and I hope it doesn't happen to them tomorrow."

Rayo Vallecano said in a statement Tuesday they were working to identify the supporter and if he was a season ticket holder, adopt the "relevant disciplinary measures".

La Liga did not immediately respond to an AFP request for comment.