By Anthony Boadle and Todd Benson
BRASILIA/SAO PAULO, July 4 (Reuters) - Neymar's exit from the World Cup due to a back injury left Brazilians shocked and angered on Friday, darkening the mood after the hosts' 2-1 win over Colombia in the quarter-finals had sparked nationwide celebrations.
The loss of their star player has dented Brazil's chances of winning a record-extending sixth World Cup, and first on home soil, and left Brazilians wondering who can replace him for Tuesday's semi-final showdown with Germany.
"Neymar fractures vertebra and is out of the Cup," the country's three main newspapers headlined in their online editions, completely overshadowing accounts of the thrilling 2-1 victory over Colombia.
The papers published blow-by-blow diagrams of the play in which Neymar was kneed in the back by Colombian defender Juan Zuñiga, burying coverage of the stunning free-kick by David Luiz that sealed Brazil's victory.
"This is terrible news. The worst possible news. Neymar is so important to us," said student Fabian Ruiz, 19, walking with friends down a street in Belo Horizonte, dressed in Brazil's trademark canary yellow shirts and quaffing beer from cans.
"Without him, the other players will have to fight more. It is going to be so difficult against Germany now."
A large crowd of fans wearing Brazil shirts gathered outside the hotel in Fortaleza where Neymar was taken after the match. As he was being taken in on a stretcher, they chanted: "Força Neymar," or, "Be strong Neymar."
Social media was flooded with messages about the incident, with many Brazilians calling on world soccer's governing body FIFA to punish Zuñiga in the same way Uruguay striker Luis Suarez was penalized for biting an Italian player.
One columnist went so far as to describe the challenge as a "savage attack."
"Neymar out of the Cup because of cowardice and foul play by the Colombian player," Fabricio Tavares, a Brazilian university professor, wrote on Facebook, echoing a common view heard on streets and in bars around Brazil.
Wishes for a speedy recovery poured in from all over, including Argentine playmaker Lionel Messi, Neymar's team mate at Barcelona.
Even Brazil's President Dilma Rousseff used her Twitter account to call on Brazilians to unite around Neymar and the national team.
Argentine soccer great Diego Maradona also lamented Neymar's injury, telling Venezuela-based Telesur TV network: "It concerns not only the Brazilian people but all of us who love football. It was his World Cup, in his country. He had great hopes."
At a bar in Sao Paulo, couples were still dancing late on Friday night to celebrate the win over Colombia, but the news of Neymar's injury dampened the mood.
"We were so happy but now it is sad. Very sad," said Monica Ferreira, 27, who watched the game at the bar with friends. "He is our best player. We love him because he plays so hard when he puts on the Brazil shirt."
Some fans thought Brazil's chances were over without Neymar.
"He is our best player. I don't think we can win the Cup without him," said a distraught-looking Eduardo Gomes, a 33-year-old fan, as he texted to find out more about Neymar's injury, drinking beer with his girlfriend sitting on his knee.
Other fans, more optimistic about their country's chances, said Brazil could pull it together and play even better without Neymar, suggesting the team had relied too heavily on him.
"At this point I don't really feel that we need him so badly," said Jair de Souza, a Sao Paulo doorman who heard the news on the radio. "It's shocking but the guys have handled worse pressure."
Narcisio, a waiter at a sushi restaurant in Brasilia, said there were other good players waiting in the wings.
"Today Neymar did not play well and our team still performed well," he said. "If we get past Germany, the Cup is ours." (Additional reporting by Andrew Cawthorne, Kieran Murray and Guillermo Parra-Bernal; Editing by Peter Rutherford)