It was not a classic head butt that put Jeremy Jacquet down deep into time added on at the end of the first half. In other cultures, in other eras, it might have been interpreted as a nod of recognition from Yehor Yarmoliuk. But it was foolish and it was enough to seal his fate and cost his team. VAR intervened, Yarmoliuk was sent off and the game was changed. Until then, Liverpool had struggled to assert themselves, even with a front line that cost more than £400m. Bradley Barcola had missed a gilt-edged chance, Florian Wirtz had spent another half fretting at the margins and Andoni Iraola’s team were soon to suffer two injury blows when both Dominik Szoboszlai and Jeremie Frimpong were forced off.But Brentford going down to 10 men wiped all Liverpool’s misfortunes away. By the time the dismissal of Vitaly Janelt reduced the home team to nine men in second half stoppage time, Liverpool were 2-1 up and heading towards fifth place in the table.The statistics said that Wirtz had created nine chances, including the assist for Liverpool’s equaliser, more than any player in the Premier League this season. That flattered his overall performance but it was something to build on. There was time for one more glaring miss from Barcola but by then it didn’t matter.It was hardly an emphatic victory. The questions about Wirtz are still getting louder. Barcola may have scored a hat-trick in the Champions League in midweek but he looks desperately short of confidence in the more testing conditions of the Premier League.Liverpool will have been buoyed by the fact it was Alexander Isak who scored the winner after Victor Munoz had dragged them back into the game with a fine equaliser but even though Liverpool have only lost once in their opening seven league games, they are still searching for something. Alexander Isak scored the winner on his return as Liverpool came from behind to beat Brentford Victor Munoz had equalised; Florian Wirtz and Bradley Barcola provided the assists ‘He is disappointed,’ Brentford manager Keith Andrews said of Yarmoliuk and his indiscretion after the game. ‘He is an amazing young man. He will learn from this. We need to look at ourselves. They were cute and clever but he needs to do better.’ Andrews is as impressive a communicator as there is in the Premier League and his reaction fitted that pattern. The game had got off to a slow start, notable only for Szoboszlai and Alexis Mac Allister blazing shots over the bar. But it suddenly came to life midway through the first half when a neat interchange between Michael Kayode and Dango Ouattara ended with Ouattara’s goal-bound shot being deflected wide by Jacquet.A minute later, Liverpool should have scored. Brentford played themselves into trouble on the half-way line and Barcola, who cost £123m when he arrived from PSG in the summer, stole the ball away from Yarmoliuk and raced clear. Barcola lifted the ball over Caoimhin Kelleher but pulled it wide of the right-hand post. ‘What a waste of money,’ Brentford’s fans sang.A fine challenge by Jacquet prevented Igor Thiago putting the home side ahead but Liverpool had other issues to deal with, too. Barcola was shown a yellow card for pulling back an opponent and then Szoboszlai had to be substituted with what looked like a recurrence of his hamstring injury.The Hungary forward was distraught. He hammered his hand into the turf in frustration. Szoboszlai has been Liverpool’s most influential player for some time so his loss was a big blow. He marched straight down the tunnel, his expression set in a stony grimace. Keane Lewis-Potter had put Brentford ahead not long before half-time with a header The game changed going into half-time when Yehor Yarmolyuk was sent off for a headbuttOne misfortune followed another. Liverpool won a penalty five minutes before half time when Mac Allister fell under a challenge from Ouattara but VAR intervened and replays showed Ouattara had touched the ball before the Liverpool midfielder tumbled to the floor.Two minutes later, Brentford took the lead. Igor Thiago curled in an inviting ball from the right and Keane Lewis-Potter ran on to it and leapt to power a brilliant header past the dive of Alisson.Deep in injury time at the end of the half, though, Brentford indulged in an act of self-sabotage. In the routine jostling that takes place before a corner, Yarmoliuk bumped chests with Jacquet and then moved his head towards the Liverpool centre half. VAR intervened again and Yarmoliuk was shown a red card for violent conduct.It was a classic ‘soft’ decision. In the press room at half time, I asked Ray Houghton if that would have counted as a head-butt in his day. ‘That would have been a friendly hello,’ he said with a smile. He was right, of course, but in today’s top-flight culture, Yarmoliuk moved his head towards Jacquet and opened himself up to the censure that followed.More injury woes afflicted Liverpool after the break. Frimpong had come on at half-time but lasted five minutes before he was led off the pitch, limping. Liverpool’s frustrations grew. Jacquet was shown a yellow card for a foul. Mac Allister was booked for dissent.Mac Allister brought a fine save out of Kelleher before Virgil Van Dijk drove a volley into the ground and watched it bounce just wide. Victor Munoz was involved in an altercation with Kevin Schade that saw Schade booked. The clash spurred Munoz on.A couple of minutes after it, he escaped down the right and sprinted into the area. He turned inside Lewis-Potter and bent a low left-foot shot around Kelleher and into the Brentford goal to bring Liverpool level.Liverpool finally looked as if they had the belief to win and eight minutes later they were ahead. Mac Allister lifted a deep cross to the back post, Barcola nodded it down and Isak got in front of his man, took one touch to control it and then rifled the ball past Kelleher. Lewis-Potter was on the line but he could only deflect it into the net.Barcola hit the bar with delicate chip but when he had a chance to put the game out of reach in the dying minutes, he hesitated, tried to play in Lewis Koumas instead and the chance was gone. It was a good win for Liverpool but it still left more questions than answers. MATCH FACTS BRENTFORD (4-2-3-1): Kelleher 7; Kayode 6, Van den Berg 5 (Hickey 71, 6), Ajer 6, Lewis-Potter 6 (Diouf 77); Yarmolyuk 4, Janelt 5; Ouattara 6 (Schade 46, 6), Jensen 5 (Sangare 46, 6), Anthony 5 (Damsgaard 78); Thiago 6.Subs not used: Valdimarsson, Carvalho, Collins, Wilson.Booked: Thiago, Schade, Janelt.Sent off: Yarmolyuk, Janelt.Scorers: Lewis-Potter 44.Manager: Keith Andrews 6.LIVERPOOL (4-2-3-1): Alisson 6; Araujo 5 (Frimpong 46 (Ngumoha 52, 7)), Jacquet 7, Van Dijk 5, Kerkez 6; Szoboszlai 5, Mac Allister 7; Munoz 7 (Gomez 79), Wirtz 7, Barcola 8; Isak 7 (Koumas 79).Subs not used: Mamardashvili, Endo, Gakpo, Nyoni, Tsimikas.Booked: Jacquet, Mac Allister.Scorers: Munoz 62, Isak 70.Manager: Andoni Iraola 6.Referee: John Brooks 4.Attendance: not provided.