Liverpool - Jay Rodriguez scored twice as West Brom pulled off a thrilling 3-2 victory at Liverpool in the fourth round of the FA Cup on Saturday in a game that will be remembered for the use of the video assistant referee.
The VAR, being trialled in English cup competitions this season, was called upon three times by match referee Craig Pawson in the opening half.
Although all three decisions looked ultimately to be correct, the incidents will do little for those opposed to the system, amid claims it disrupts the normal flow of the game.
Leading 2-1 after 19 minutes, Albion believed they had scored a third goal after Craig Dawson headed in from a corner, although it quickly became evident that Pawson was uncertain.
After at least two minutes, and consultation with VAR official Andre Marriner in a studio in London, Pawson disallowed the goal for an offside decision against Gareth Barry, who had been standing in front of Liverpool goalkeeper Simon Mignolet.
If Albion were unhappy with that decision, they were furious just four minutes later when Liverpool forward Mohamed Salah went down heavily in the penalty area after what appeared to be a tug on the arm by Jake Livermore.
Once more the VAR was summoned before Pawson, moving to look at a touchline screen, became the first English referee to directly consult a replay.
Pawson eventually pointed to the penalty spot after a delay that mounted well over three minutes.
Firmino took the spot-kick only for the ball to hit the the underside of the crossbar before it was cleared by West Brom.
There was yet more controversy when, in first-half injury-time, West Brom did claim their third goal after Dawson drove a low shot, from a wide angle, towards the far post.
The ball seemed to take a deflection off Liverpool defender Joel Matip on its way into the goal although Albion's Rodriguez was also poised at the far post in what appeared an offside position.
Pawson once more consulted the VAR and, again, appeared to reach the right decision in awarding the goal.
The delays -- totalling more than seven minutes in total -- detracted from an absorbing half of football and three goals inside the opening 11 minutes.
After just five minutes, Jonny Evans failed to deal with Chris Brunt's back pass, allowing Salah through on goal where he was denied by keeper Ben Foster's block.
The ball fell kindly for Firmino on the edge of the area and the Brazilian sent a superb, deft chip over the keeper's body and into the open net.
Albion were level within 65 seconds, however, after Georginio Wijnaldum lost the ball and Brunt picked out the run of Rodriguez who planted a magnificent shot past Mignolet from just inside the area.
Four minutes later and Rodriguez was again on the mark, this time turning in from close range from Kieran Gibbs's cross although the goal owed much to brilliant midfield play and a pass wide from Grzegorz Krychowiak.
Nor was the drama limited to officiating and goal-scoring. Twice within a minute, Albion lost players to muscular injuries -- Gibbs and Hal Robson-Kanu leaving the field - meaning they had used two of their substitutes by the 38th minute.
After a more sedate start to the second half, Liverpool manager Jurgen Klopp made a triple substitution after 65 minutes, bringing on Jordan Henderson, Danny Ings and James Milner and the trio helped transform the tie.
Finally by the 73rd minute, Liverpool had raised their game with Foster making superb saves in quick succession from Milner and Ings and, in the 78th minute, Liverpool were within a goal of an unlikely draw when Trent Alexander-Arnold's driven cross was mis-controlled by Firmino and Salah pounced on the ricochet, driving the ball home from 12 yards.