The 22-year-old Brazilian international forward was targeted during a 1-0 defeat at Valencia on Sunday and was later sent off.
Vinicius issued a strongly worded statement afterwards saying that La Liga "belongs to racists" and several Brazilian players past and present offered their support.
Brazilian President Luiz Inacio Lula da Silva condemned the abuse, telling a news conference at the close of the G7 summit in Hiroshima, Japan: "He was attacked. He was called a 'monkey'."
Vinicius has frequently been targeted in La Liga and the latest incident came at Valencia's Mestalla when he was racially abused by a home supporter.
Vinicius stood in front of fans behind the goal and pointed to the apparent culprit. Play was delayed for several minutes in the second half.
Referee Ricardo de Burgos Bengoetxea spoke to stadium officials, who made an announcement calling for racist insults to stop before play resumed around 10 minutes later.
In his post-match report, the referee wrote that a fan shouted "monkey, monkey" at the player.
Vinicius was sent off in added time at the end of the game for hitting Hugo Duro during a brawl, with Valencia triumphing through Diego Lopez's first-half goal.
Vinicius left the pitch making a gesture with his hands indicating Valencia were heading down to Spain's second division.
- Stop the game, says Ancelotti -
Real Madrid coach Carlo Ancelotti said Spanish football needed to be prepared to halt matches.
"The Spanish league has a problem, and Vinicius is not the problem. Vinicius is the victim. There's a very serious problem," Ancelotti said.
"The fact I thought about taking him off because of the racist atmosphere does not seem good to me," Ancelotti told reporters.
"What has happened today has happened before, but not like that, it's unacceptable."
Vinicius has been racially abused at several stadiums this season in Spain and an effigy of him was hung from a bridge in the Spanish capital by Atletico Madrid fans.
La Liga have filed legal complaints to Spanish authorities on multiple occasions this season, with the league pledging on Sunday to do so again after investigating.
However, Ancelotti said it was not helping.
"What has happened? Reports, and nothing at all has come from it. The solution is to stop the game," said the veteran Italian.
Writing on Instagram, Vinicius said Spain was viewed as "a country of racists" in his homeland.
"The prize for the racists today is that they have sent me off. It's not football, it's La Liga," he said.
"The league that once belonged to Ronaldinho, Ronaldo, Cristiano (Ronaldo) and Messi now belongs to racists," added Vinicius.
La Liga said in a statement that they were investigating the incident and would take legal action if a hate crime had been committed.
The Spanish top flight said they have been "proactive" in previous cases of racism against Vinicius, filing nine complaints with relevant authorities and prosecutors.
- 'Love and support' -
Vinicius has received widespread support.
Madrid goalkeeper Thibaut Courtois said he heard "monkey noises" after about 20 minutes of the game and said he would have walked off with Vinicius if the Brazilian chose to stop playing.
"If Vini wants to keep playing, we keep playing, but if Vini says he's not playing any more, I'm leaving the pitch with him because we cannot tolerate these things," Courtois told Movistar.
Former England defender Rio Ferdinand said Vinicius needed more protection from Spain's football authorities.
"I see pain, I see disgust, I see him needing help," he wrote on Instagram.
There was anger among many in Brazil.
President Lula called for FIFA and the Spanish league to take "serious measures".
"It's unjust that a poor kid who's done so well in life, who may be on his way to becoming the best in the world -- he's certainly the best at Real Madrid -- gets insulted at every stadium where he plays," he said in Japan.
On Twitter, Brazilian Football Confederation president Ednaldo Rodrigues said: "Vini Jr., you have our love and support, and that of all Brazilians."
The forward's fellow Brazilian international Richarlison, retired legend Ronaldo and music icon Gilberto Gil were among those who condemned the racist treatment he has received in Spain.
"Another episode of racism in La Liga. And once again Vini Jr. is the victim. How long will this last?" the 46-year-old Ronaldo wrote on Instagram.
"As long as there's impunity and complicity... Enough."
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