Barcelona midfielder Sergio Busquets angrily denounced the performance of referee Wolfgang Stark after Tuesday's 2-2 Champions League quarter-final first leg draw at Paris Saint-Germain.
In a dramatic evening at the Parc des Princes, Lionel Messi put Barca ahead, then left the game injured at half-time. The Catalan side appeared to be controlling proceedings at 1-0 ahead, until PSG got back into the tie with a controversial Zlatan Ibrahimovic equaliser.
Barca defenders Jordi Alba and Javier Mascherano were ordered off the pitch to receive medical attention by Stark, as play continued. Barca cleared the subsequent corner, and the pair returned, but moments later Ibrahimovic scored from close range after a Thiago Silva header had hit the post.
Replays showed the Sweden international had been clearly offside when poking the ball home, and the official behind the goal and linesman both had a clear view of the incident.
Busquets told reporters after the game that Stark had apparently wanted PSG to get back into the game.
"Ibra was one or two metres offside in his goal," Busquets said. "It is incredible that the linesman has not seen it, it was a clear offside. The referee did not relax until they equalised. They whistled us up for any small thing, while PSG players were let off yellow cards even though they were committing fouls."
Barca had been on the wrong end of a similarly poor decision in their last-16 first leg at Milan, Busquets said.
"We already had problems in Milan, with the handball [by Cristian Zapata] which lead to [Kevin Prince] Boateng's goal which was not called," he said. "This is the Champions League ... but there is nothing we can do. This is football, now it is up to us to win at home."
Barca went back in front late on Tuesday night via Xavi Hernandez from the penalty spot after PSG goalkeeper Sirigu was judged to have upended Alexis Sanchez inside the box, a decision which was heavily criticised by home coach Carlo Ancelotti. The French side then equalised again in the 94th minute when Blaise Matuidi's shot deflected past Catalan 'keeper Victor Valdes.
German official Stark was well known to the Barcelona players for sending off Pepe for a foul on Dani Alves in their 2011-12 semi-final first leg at Real Madrid, a decision which lead to Jose Mourinho's infamous airing of a conspiracy theory involving UEFA and UNICEF.
Speaking with Barca TV, having had more time to reflect, Andres Iniesta gave a more measured response to how the official's performance had affected the game.
"It is easier to have a bit more perspective after you have cooled down a bit," Iniesta said. "It was a shame. It seems easy to spot, but the [officials] are human and they make mistakes. When it is your turn, well of course it hurts you. The most important thing is we played a very good, serious game. We just have to try and win at home, we have no other option."