Chelsea manager Antonio Conte has come down heavily on the Video Assistant Refereeing (VAR) system saying it must be improved after his team narrowly overcame Norwich City in a dramatic FA Cup third round replay clash at the Stamford Bridge here.

The VAR system, now being trialled in both domestic cup competitions this season, came under the scanner when referee Graham Scott judged Willian to have dived in an attempt to win a penalty and showed him a yellow card during the match which ended 1-1 in regulation time before nine-man Chelsea won 5-3 in tie-breaker on Wednesday.

Norwich’s Tom Klose, who was with Willian when he was adjudged to have dived, admitted after the match that he felt he caught the Brazilian.

But as video official Mike Jones did not see a clear error in Scott’s decision, the incident was not subject to a full review.

During the match, Michy Batshuayi put Chelsea in front in the 55th minute before Jamal Lewis headed in the equaliser in the 94th minute to send the tie to extra-time and subsequently penalty shootouts.

“I think that we need to improve if we want to use this new system,” Conte was quoted as saying after the match by ESPNFC.

“The referee took quickly a decision to book Willian. That means you don’t have doubt. If we want to improve we have to wait to check with the person who is watching the game and then, if this person is sure 100 percent that it is simulation, go and book Willian. Instead, I think the person watching the game at least must have a doubt. There is a kick to Willian and he should call the referee and tell him.

“If we want to use a new system, I can’t accept a big mistake. In this case, the Willian penalty was a big, big mistake. Not from the referee on the pitch, but from the person watching the game. If you’re watching the game and don’t see this situation … 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 and must improve.”

Chelsea were reduced to nine men in extra-time after Pedro, earlier booked for diving, caught Wes Hoolahan late and Alvaro Morata was shown a second yellow for dissent as he protested being penalised for diving in the box.

Asked why his players had dived, Conte replied: “I don’t know, but I don’t want an advantage. About Pedro, if there is a dive, it’s right to take a yellow card. It’s the same for Morata.”

Chelsea now take on Newcastle United at home in the fourth round on January 28.

“We have to try to recover very well, for sure,” he admitted.

“I hope we don’t pay. My decision was very clear: To try to go to the next round and give a bit of rest for the other players. But it won’t be easy against Brighton. It’ll be important to rest and recover. Also two red cards, so Pedro and Morata cannot play.”