Chelsea manager Antonio Conte and his Arsenal counterpart Arsene Wenger have questioned aspects of the VAR system after it was used during their goalless League Cup draw on Wednesday.
The system reviewed two penalty decisions, one for each side, during the first leg of the semi-final clash with match referee Martin Atkinson and VAR assistant Neil Swarbrick agreeing that neither incident warranted a spot kick.
Conte said he was "positive" of the new technology but was frustrated with the insufficient stoppage time at the end of the second half to accommodate for delays caused by VAR and injuries.
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"For me, there's disappointment about [not enough] extra time," the Italian told Sky Sports. "In the second half, the doctor went onto the pitch twice and the referee stopped for VAR, so you have to give more minutes of extra time.
"In Italy, sometimes extra time can be seven, eight or nine minutes."
Wenger questioned the delay between the incident and the VAR review after the second penalty appeal, following Danny Welbeck's tackle on Cesc Fabregas in the box, was turned down by Atkinson but reviewed after several minutes.
"There were only two opportunities for them to intervene, the first one was straight away because the ball went out," Wenger said after the match.
"But the second one for me it would look a bit strange ... if the referee is uncertain maybe he should be able to block straight away.
"If there is no penalty, you give it to the defending team, because it looks a bit strange to go on for two minutes for example sometimes and then to come back ... You cannot intervene straight away, it's frustrating."
The VAR system was being given its second outing in English football after being successfully tested in Monday's FA Cup tie between Crystal Palace and Brighton & Hove Albion.
English Football Association chief executive Martin Glenn has previously backed the technology to become a permanent fixture in English football with a concrete decision on its implementation yet to be reached.