The Benfica president, Rui Costa, has apologised to his Real Sociedad counterpart after visiting supporters threw flares on to home fans during their Champions League meeting on Wednesday night. There was also trouble in the streets around the Reale Arena before the game with a group of around 50 ultras throwing fireworks and sticks. Ten people needed medical attention and four arrests have been made so far. “We will pursue them legally,” said the Real Sociedad president, Jokin Aperribay, “if these delinquents have to go to jail, they will go.” The referee Anthony Taylor had to pause the game when fireworks were thrown onto the pitch during the match, which Real Sociedad won 3-1, and flares were also thrown from the away section on to the home supporters below. Midfielder Mikel Merino said afterwards that there had been moments when the players’ minds were not on the game. Television and security footage captured the incidents and some of those involved have identified by the authorities. Of the four men initially arrested, three were Portuguese. One is from San Sebastián but, Real Sociedad insisted, he is not a member. Benfica had appealed prior to the game for good behaviour from their supporters. “Despite the calls over the last few days for there to be no incidents, that did not happen and we have to apologise for this episode,” a statement from the Portuguese club said. “Benfica is committed to collaborating fully with the relevant authorities to ensure that this behaviour is not repeated.” “Benfica’s president is absolutely ashamed, he said sorry repeatedly,” Aperribay said. “I am sure there are many people from Benfica who have nothing to do with this. I would ask our fans [to be aware] that this is not the fault of Benfica supporters in general; it is four or five delinquents who threw flares and brought them into the ground. What happened in the afternoon is that some Benfica fans who were not controlled went for our supporters. It’s an issue of civic security. What is happening in some games is horrendous.” “Real Sociedad will pursue those who have thrown flares and will try to ensure that they are brought to justice. Some of them have been identified. Our checks were exhaustive but unfortunately some managed to sneak [flares] into the ground. There are sufficient cameras in the visiting section to be able to identify them so that the police know who they are.”