Bundesliga: VAR controversies

Matchday 4: With Dortmund in a 1-0 lead over Cologne, Sokratis (third from right) scored from a corner just before the break. Referee Patrick Ittrich ruled it no goal because he had whistled the play dead before the ball crossed the line. The VAR overruled him and the goal stood. Cologne were left wondering how a goal scored after the whistle could be counted. Dortmund went on to win 5-0.

Matchday 4: Wolfsburg goalkeeper Koen Casteels rammed his knee into the face of Stuttgart's Christian Gentner, causing him multiple facial fractures as they both went for the ball. The referee waved play on, refusing to consult the VAR to see if a foul had been committed. Gentner, who also suffered a concussion, had to undergo two operations and was knocked out of action for weeks.

Matchday 5: Frankfurt's 1-0 victory over Cologne was the result of a VAR penalty decision.Timo Horn (right) attempted to poke the ball away from Mijat Gacinovic. The VAR ruled it a foul and a penalty was called even though it was clear that the ball bounced up after Horn had made contact with it. Sebastien Haller converted the spot kick to secure the victory for Frankfurt.

Matchday 8: With the match tied at 1-1 in injury time, Cologne's Sehrou Guirassy (right) and Stuttgart's Dennis Aogo (middle) collided in Stuttgart's area. Referee Benjamin Cortus gave Cologne a penalty, but the VAR reversed the on-field decision despite what most agreed was inconclusive video evidence. Chadrac Akolo scored the winning goal moments later to hand Stuttgart a 2-1 win.

Matchday 10: Shortly after kickoff between Stuttgart and Freiburg, Daniel Ginczek (left) challenged Caglar Söyüncü (right) for the ball. Söyüncu's hand touched the ball, and Ginczek argued that he had done so on purpose. The VAR agreed and found that Söyüncü had denied Ginczek a goal-scoring opportunity. Therefore he was was sent off - much to the dismay of Freiburg coach Christian Streich.

Matchday 12: Already down 1-0, a VAR decision 14 minutes into the game gave Hertha Berlin even more grief. Gladbach's Lars Stindl fired a shot off the arm of Karim Rekik (left) and referee Bastian Dankert (right) initially gave a corner. But the VAR ruled it a handball, which also meant that Dankert had no choice but to give Rekik a yellow card. Gladbach went on to win the match 4-2.

The man put in charge of implementing VAR in the Bundesliga, former FIFA referee Hellmut Krug, was removed from his post by the German Football Association (DFB) in early November. Krug had been accused of wrongly influencing VAR decisions - a charge he has vehemently denied.

Matchday 13: The Signal Iduna Park errupted when Pierre-Emerick Aubameyang (right) scored the opening goal for Dortmund in the Revierderby. But the video replay clearly showed that the Gabonese striker's hand had touched the ball as it crossed the goal line. The VAR didn't intervene, but Schalke had the last laugh as they reversed a 4-0 deficit at the half to earn a 4-4 draw in injury time.

Matchday 23: Veteran striker Claudio Pizarro thought he'd secured a vital victory and his first goal for Cologne after scoring with a diving header in stoppage time against Hannover. However his and the fans' celebrations were cut short after the goal was correctly ruled out for offside after consultation with the video assistant referee. The match finished in a 1-1 draw.

Matchday 30: Referee Guido Winkelmann had blown the whistle to end the first half and the two teams were in the dressing rooms when the VAR told him that Freiburg's Marc-Oliver Kempf had handled the ball in his penalty area shortly beforehand. Winkelmann called the two teams back onto the pitch so that the penalty could be taken. Pablo de Blasis buried it for Mainz' first goal in a 2-0 win.