The Video Assistant Referee (VAR) system was getting a workout during the first half of Liverpool's FA Cup fourth round clash against West Brom.
Jurgen Klopp's side were looking to bounce back following their shock 1-0 defeat to Swansea City on Monday night.
Roberto Firmino gave the hosts the lead before a quickfire Jay Rodriguez double put West Brom 2-1 in front within 11 minutes.
Plenty of fans inside Anfield booed at the half-time whistle after a Joel Matip own goal gave the visitors a shock 3-1 lead.
Unbeaten at home this season, Liverpool incredibly beat Manchester City 4-3 in the most recent fixture at Anfield.
It was a thrilling first half of action but all the attention was on the video assistant referee.
VAR used on three separate occasions
West Brom had a goal disallowed by VAR after going 2-1 up - and the players were furious soonafter when Liverpool were awarded a penalty due to the intervention of VAR.
Mohamed Salah went down under a challenge from Jake Livermore in the box and - after almost four minutes of uncertainty - a penalty was finally awarded.
The penalty was missed by Firmino but VAR was called upon once more to check that West Brom's third goal was indeed a goal.
Joey Barton tweets about VAR
It's only the sixth time the system has been used in English football - and some are beginning to form their opinions on VAR.
Whilst most football pundits stayed quiet on social media, BT Sport pundit Michael Owen shared his thoughts on VAR.
Former Premier League midfielder Joey Barton also tweeted opinion after an eventful first half at Anfield.
He raises an excellent point.
Match tickets are not cheap in England and fans in the stadium had absolutely no idea what was going on whilst the referee came to a final decision.
Yet to be introduced in the Premier League, VAR is expected to be used at this summer's World Cup in Russia.
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