Antonio Conte has suggested the video assistant referee, Mike Jones, was guilty of a “big, big mistake” after opting not to flag up a potential penalty as Chelsea’s third round replay victory over Norwich City descended into farcical scenes in extra-time.

The hosts, who would prevail on penalties, were reduced to nine men following the dismissals of Pedro and Álvaro Morata, who were both shown one of their two yellow cards for diving. Willian was also cautioned for going to ground in an incident with Timm Klose.

Conte watched a replay of that challenge and was insistent it should have resulted in a spot-kick, but the VAR apparently decided no clear and obvious error had occurred.

“If we want to use a new system, I can’t accept a big mistake,” he said. “In this case, the Willian penalty was a big, big mistake. Not from the referee on the pitch, who took quickly a decision to book Willian and didn’t have any doubt, but from the person watching the game [Jones]. I hope the VAR wasn’t a referee because if you see that watching on television and don’t think that’s a penalty … he has to improve. It was very clear.

“At least to avoid a big mistake, [the VAR has] to call the referee and tell him: ‘Look, maybe this situation there is a doubt. For me it’s no penalty, but it’s better you go and watch it, and then take the final decision.’ We need to improve if we want to use this new system. We have to wait to check with the person who is watching the game and then, if this person is sure 100% that it is simulation, go and book Willian.”

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Klose subsequently admitted he had caught his opponent. The Chelsea head coach said Pedro and Morata deserved yellow cards for diving – he had not seen a re-run of the striker’s tumble away from Christoph Zimmermann – and the pair are now banned for Saturday’s trip to Brighton.

“About Pedro, if there is a dive it’s right to take a yellow card,” said Conte. “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.”