Antonio Conte was left fuming with the referees as Willian was not only turned down for a penalty appeal in the first half of injury time but he was booked for diving after Norwich's Timm Klose made contact with his leg in the box.
Chelsea struggled past Norwich City on the night as Michy Batshuayi's opener was cancelled out by Jamal Lewis's stunning header in the 94th minute of normal time. The game went into extra time and no goals were scored, though Pedro and Alvaro Morata were both sent off. The Blues then won 5-3 on penalties, with Eden Hazard netting the winning spot kick.
However, VAR became a huge talking point as the referee arguably made a mistake over a penalty decision despite having the tools at his disposal. Conte went on an extended rant as journalists quizzed him over the new system which has its first controversy in English football.
“I think that we need to improve if we want to use this new system," Conte said at Stamford Bridge. "Today, in this game, there is a situation very clear with Willian at the start of the first period of extra-time. I think the situation was very clear. I watched it and this is a penalty. Very clear.
"But this is not because I'm not happy with a referee's decision. The referee took quickly a decision to book Willian. That means you don't have doubt. If you do this quickly, it means you don't have doubt.
"Instead, I repeat, if we want to improve – it's only to try and improve the system – we have to wait to check with the person who is watching the game and then, if this person is sure 100 per cent that it is simulation, go and book Willian. Instead, I think the person watching the game, at least you must have a doubt.
"There is a kick to Willian and he should call the referee and tell him. Maybe it's a penalty, for me. In Italy, before to arrive to use this new system, they tried, tried, tried... But if you want to try quickly this new system, then you have to find the best solution.
"For me, this is not the right solution if the referee doesn't refer a doubtful decision. The final decision stays with the referee on the pitch, not the one watching the game. But it's only because we want to try and use this new system, and this is my opinion to help the referee use this new system.
"We have been using it in Italy for six months, and you can reduce a lot the referee's mistakes. But you must be sure, 100%. And, despite this, there is another person checking the situation.
"If the person checking the situation calls you and says it's a penalty, you say you made a mistake, take back the yellow card and give the penalty. I think we have to find the right solution to try to help the referee.”
Chelsea had three players booked for diving during the match and five yellow cards with Pedro and Morata's red cards meaning that they will miss the upcoming Premier League game against Brighton on Saturday.
Conte conceded that he was unhappy with Pedro for diving, while he thought Morata's first yellow card was a little harsh. He did add that Morata shouldn't have reacted to get his second yellow card for dissent.
“I don't know, but I don't want an advantage [by cheating]," Conte added. "About Pedro, if there is a dive, it's right to take a yellow card. It's the same for Morata. I don't want an advantage, especially if you know this system is being used.
"You can watch every situation with this situation. If someone gives a punch or an elbow, you must pay great attention. In this case, if it wasn't a penalty, it was right to give a yellow card.
“For sure, I'm not happy for the second yellow card for Morata. The first yellow card was for a doubtful situation – I didn't watch Morata's situation yet – but the second was for dissent. You must pay great attention. In this moment of the game, you have to pay great attention to stay calm and make the best decision.”
Chelsea's win in over 210 minutes of football in the FA Cup third round against Norwich City has set up a fourth round tie against Newcastle United at Stamford Bridge. The match will take place on 28 January.