Liverpool's extraordinary attention to detail has enabled them to master underappreciated art form

Many an eyebrow was raised back in the summer of 2018 when it was announced that Liverpool had hired a specialist throw-in coach to bolster their backroom set-up. TV pundit Andy Gray ridiculed the appointment, while rival fans on social media mocked it as through it were ludicrous that such a thing should even exist, let alone make a tangible difference to Liverpool's performance level.

In fairness, Thomas Grønnemark – who once set the world record for the longest throw in at 51.33m – himself described his vocation as "the weirdest job in the world", while Jürgen Klopp admitted he'd "never heard about a throw-in coach" before. But as Klopp explained: "When I heard about Thomas, it was clear to me I wanted to meet him; when I met him, it was 100 per cent clear I wanted to employ him. You cannot have enough specialists around you."

Indeed, one of the most overlooked aspects of Klopp's reign has been the way he has constructed a cutting edge backroom team of elite level specialists in their field, including bringing nutritionist Mona Nemmer and fitness coach Andreas Kornmayer from Bayern Munich. No stone has been left unturned in the pursuit of every possible marginal gain, and that ethos underpinned the decision to appoint a throw-in specialist.

As Grønnemark explained to BBC Sport upon his arrival: "If you are expecting professional footballers to be world-class throwers without coaching then you are pretty optimistic. Generally the standard is quite poor. No matter what position in the league, throw-ins are an advantage."

And he was absolutely right. In September 2019, an excellent mini-documentary produced by Tifo Football cited that the Premier League was the worst of any major league in Europe for average possession retained from throw-ins (48.6 per cent), while in 2017/18 prior to Grønnemark's appointment, Liverpool retained possession only 45.5 per cent of the time from throw-ins, making them the third-worst side in the league in that regard.

But the following season, after Grønnemark's arrival, Liverpool retained possession 68.4 per cent of the time from throw-ins, making them the second-best team in Europe for throw-ins, after Danish Superliga side FC Midtjylland – unsurprisingly, also coached by Grønnemark. The angle and trajectory of throw-ins is a key aspect of his work, which, as Tifo explain, resulted in Andy Robertson increasing his throwing distance from 19 to 30 metres, while Joe Gomez picked up an assist directly from a throw-in for England against Croatia in November 2018.

Given that there are on average between 40-50 throw-ins per game, it seems entirely logical to hone this skill as well as possible, turning it into a mechanism to create chances and relieve pressure, as opposed to aimlessly hurling the ball back into play and hoping to win a flick on.

Grønnemark has spoken about how throw-ins are about more than just technique, "but how to receive it, how to make the right runs, the positioning, creating space", as well as taking them quicker (within five seconds of the ball going out of play) before opposition sides have the chance to set up defensively.

That has been put into practice to great effect in two of Liverpool's most recent victories, firstly for Roberto Firmino's goal in the 1-0 away win against Tottenham Hotspur, as Andy Robertson launched a throw-in into the Brazilian's path. A few seconds later, the ball broke to Jordan Henderson on the egde of the box, before Mohamed Salah shifted it back to Firmino to fire across goal for what proved to be the winner.

Then again, against Wolves on Thursday night, Liverpool found themselves more on the ropes than they have done arguably all season, until Trent Alexander-Arnold launched a throw in from the right-hand side towards Firmino. This time, he let it run to Salah, who then worked it to Henderson on the edge of the box, as the captain slid Firmino in to rifle home the winner on his left foot once more.

Two decisive goals of remarkable symmetry, involving the trident of Henderson, Salah and Firmino, all started with an intelligent throw-in taken by one of the full-backs. It's easy to overlook in real time, but it's precisely this forensic attention to detail which has enabled Liverpool to manipulate every possible scenario to their benefit.