Chelsea manager Antonio Conte backed the video assistant referee (VAR) system after his side's goalless draw with Arsenal in their Carabao Cup semi-final first leg.
Referee Martin Atkinson consulted the VAR on two Chelsea penalty claims, when Victor Moses tangled with Ainsley Maitland-Niles in the first half and for Danny Welbeck's last-minute challenge on Cesc Fabregas, but he was satisfied enough with the evidence relayed to him not to award a spot-kick.
"I am very positive about VAR because when there is a big doubt during the game it is right the referee and the other referee watch the video to check and make the best decision," Conte said.
"I think everyone wants less mistakes during the game and I think this could be very positive for sure."
The two sides will meet in the second leg at Emirates Stadium on 24 January after Arsenal showed resilience following Sunday's FA Cup third-round defeat by Nottingham Forest to frustrate a strong Chelsea team.
"It was a good performance," Gunners manager Arsene Wenger said.
"We were well organised. It was a good draw and we have to finish the job."
Arsenal were the beneficiaries of careless Chelsea finishing, with Fabregas and Andreas Christensen culprits with poor headed efforts, while keeper David Ospina saved well from Moses and Alvaro Morata.
Alexandre Lacazette blazed Arsenal's best chance over the bar in the first half but there was no doubt they were happier with the result to set up the second leg at Emirates Stadium.
After making its debut in Monday's FA Cup third-round tie between Brighton and Crystal Palace, the video assistant referee was once again used at Stamford Bridge - and it provided moments of frustration, confusion and tension.
Referee Atkinson consulted it to adjudicate a first-half incident before a set-piece when Chelsea's Cesar Azpilicueta clashed with Calum Chambers, eventually lecturing the pair, and again when Maitland-Niles tumbled under a challenge from Moses.
It resulted in a brief delay, with Arsenal's fans chanting "VAR", before Atkinson stuck with his original decision - but there was an anxious moment for Arsenal in the closing minutes when Welbeck made a tackle which needed to be perfectly timed in the area on Fabregas.
It was then when another sight that will be become increasingly familiar was witnessed, with Chelsea manager Conte effectively appealing to fourth official Jon Moss for VAR by making the shape of a television screen.
A long delay, some would argue too long, ensued before Atkinson delivered what was clearly the correct decision - no penalty.
"You have to improve and understand that when you start to use VAR you then need to add more extra time," Conte said. "When there are doubts about two situations in the game then the extra time is seven, eight or nine minutes."
Wenger added: "It was interesting. It was a cause of anxiety as it took a bit of time to make the second decision with Welbeck and Fabregas, but overall it worked well.
"But between the penalty action or penalty not action, with the time taken it would have been strange to come back to the penalty."
Chelsea wasteful as Arsenal hold firm
Chelsea had the opportunities to build an advantage for the second leg - but found Arsenal in resilient mood and wasted the chances that presented themselves.
Arsenal needed a show of strength after Sunday's embarrassing FA Cup exit to Nottingham Forest and showed steel, with Shkodran Mustafi and Calum Chambers excellent in defence.
Fabregas wasted a clear headed chance in the first half, while Christensen was also profligate - which led to frustration for manager Antonio Conte and an animated discussion with the match officials after the final whistle.
Full-time in this low-key game was greeted with virtual silence by Chelsea's fans.
Chelsea's quality is such that they have certainly not missed their chance but their carelessness means they have made life more difficult for themselves when they travel to Arsenal in a fortnight.
"We are about 50/50 because don't forget not to concede a goal at home could be very important for the second leg," Conte said.
"At the same time we know that to play at Emirates Stadium is not easy but we are ready."