The fans chorused “VAR”. So did the West Bromwich Albion supporters, only with an expletive before it. 

On a night of new technology in the oldest competition of them all, the drama came on and off the field. 

A classic FA Cup tie had a different feel. It had a traditional shock. Because West Brom had only beaten one top-flight team since August. Liverpool had not lost at home since April. 

That all changed amid the chaos of a cracking game. It was a triumph for Chris Brunt. At fault for one goal, he made two. 

It was a great evening for Jay Rodriguez, who ran Liverpool ragged. It was an awful one for Jurgen Klopp’s side, who defended disastrously. 

The German has the wrong sort of 100% record in the FA Cup. He has gone out in the fourth round in every year in charge. 

His team failed to score in 90 minutes against Albion last month and lost a lead in 90 seconds this. 

When Brunt guided a pass back, Ben Foster refused to leave his penalty box. Mohamed Salah raced on to it instead and, though Foster did well to save his shot, the ball fell for Roberto Firmino. 

He measured his chip beautifully, finding the unguarded net for his 11th goal in 13 starts. 

 Brunt more than made amends. Having found Salah with one pass, he picked out Rodriguez with another. 

The in-form forward rifled a shot into the back of the net. Four minutes later, the same combination worked beautifully again. After Grzegorz Krychowiak surged forward, Brunt centred and Rodriguez applied the finish. 

Having scored at Goodison Park last Saturday, he did not just repeat the feat across Stanley Park seven days later. He struck twice. 

It carried on Albion’s habit of grabbing early goals. Then came trial by television. Albion were celebrating a third goal when Craig Dawson headed in Brunt’s corner. 

Referee Craig Pawson awarded the goal, but consulted the television official who saw Gareth Barry offside and interfering with play. 

It was a let-off for the recalled Simon Mignolet, who showed why he had been dropped in the Premier League by remaining rooted to his line when Dawson attacked the ball. Not that the VAR drama was over.

Four minutes later, Jake Livermore tugged Salah. Pawson ruled it was not a penalty. The Liverpool players persuaded him to look at the monitor on the touchline. He changed his mind. 

Anfield cheered until Firmino’s spot kick came back off the bar. And there was a third stoppage to consult the footage when Albion did score again. 

Dawson, who was just onside, hooked a low centre across the six-yard box. Joel Matip tried to backheel the ball clear and instead touched the ball into his own net. 

Salah pulled a goal back but despite losing two injured players and despite VAR, Albion stunned Anfield.