The calculators were out at the Gtech Community Stadium.

A quick maths lesson in the media room before kick-off deduced that Liverpool’s front four cost a whopping £399.5million.

The quartet of Alexander Isak (£125m), Bradley Barcola (£123m), Florian Wirtz (£116m) and Victor Munoz (£35.5m) had started just one game together before and that, a home match against Fulham, ended in a goalless draw.

So the knives would have been out if those had blanked and the Reds had left a bitterly cold west London armed with anything but three points.

This is a tricky place to go and many big teams falter on this turf but, given they started the weekend nine points behind the league leaders, this was must-win for Andoni Iraola.

In the end, Wirtz threaded in Munoz for a splendid goal to equalise, then Barcola picked out Isak to finish for 2-1. Any narratives about Liverpool’s big-money flops were put on hold – for now at least – and, instead, the away fans could toast to their awesome foursome.

Liverpool’s clash with Brentford was a must-win for Andoni Iraola – and his side delivered

The prolific and ruthless forward line does not tell the full story of this game. Far from it. For large parts, Liverpool were stodgy and, had Brentford not gone down to 10 men late in the first half, this could have easily ended up a completely different outcome.

These things even themselves out over the course of the season, we are often told, and after being left aggrieved at Ryan Gravenberch’s red card that ruined their chances last week, this time they were left thankful for Yehor Yarmolyuk’s bizarre headbutt and subsequent sending off.

Until then, the Reds were looking vulnerable and at risk of falling to the same fate they suffered on this ground last year, when Brentford bullied Arne Slot’s side and exploited many weaknesses.

Some of those issues are still clear but Iraola is now using his own weapons to help win games. Last year, Liverpool could not hurt teams and then were too flimsy at the other end.

The chief reason for this is Isak, all £125m of him.

His goal was his fifth of the season which sees him surpass last term’s tally already. Without his goals, Liverpool would be six points worse off and in the bottom half.

That might be a stretch but his brace in a 2-0 win at Ipswich, strike in a 1-0 victory at Bournemouth and now the match-winning goal in this 2-1 triumph has helped three tricky away trips turn from draws to wins.

With him fit last Sunday against Manchester City, who knows whether the Reds would have taken one of their early chances at 0-0 and made the game an alternative spectre.

Alexander Isak scored the winner at Brentford. He is not Liverpool’s best player – but he is their most important

Bradley Barcola may have been wasteful at time but he dazzled again after his Champions League hat-trick

Isak is the sort of player who can drift in and out of games. But that is what the best strikers do — just think of the amount of time Sky Sports have highlighted Erling Haaland’s lack of touches only for the Norwegian to make them look silly by winning the game with his next shot.

The Swede, then, may not be Liverpool’s best player but he is certainly their most important. Three match-winners already this term, one can only wonder how different last season might have been if this instinctive poacher was fit all year.

His fitness is still questionable and it would not be a surprise to see him rested for Tuesday’s Champions League match against Villarreal for that reason.

Isak scored the winner but the supporting cast in attack also caught the eye. Munoz, the lesser-heralded of the star forwards, scored a fine goal from the right-hand side at a time when it felt Brentford were starting to settle into playing with 10 men.

Rio Ngumoha, a substitute, is also worthy of praise and he was a contender for man of the match. Against stubborn defences like this opposition, the 18-year-old’s unorthodox style is devastating and a real tool.

Barcola was wasteful but still dazzled at times. The Frenchman had clearly left his shooting boots in Austria and looked shaky in front of goal after his midweek hat-trick at LASK, but this was another notable performance, including an assist.

He was at the heart of everything, as was Wirtz. The German has been criticised this week — some of it harsh, most of it fair enough — but this was a metronomic display, creating nine chances which is more than any Liverpool player on record in a Premier League fixture.

More of this from the attackers and Iraola knows the possibilities are endless, though he would have boarded the flight home knowing his team remains a work in progress.

With a full contingent of players, Brentford would have been a good bet to get at least a point, and Iraola might worry at how many times the Bees got in behind his defence in the first half.

There are also battle scars with Dominik Szoboszlai and Jeremie Frimpong set for ‘some time’ on the sidelines with muscular injuries. It is unclear how serious either are with the duo set for scans in the next 24 hours.

But despite the fitness worries and minor teething problems that still need solving, the Liverpool boss can raise a glass knowing his £400m attack is heading in the right direction.

With Isak et al on form and remaining fit, the Reds can prosper this year.