Arsenal will deploy a potent weapon who never sets foot on the pitch when they bid to exploit Paris Saint Germain's set-piece vulnerability in Tuesday's Champions League showdown.
Mikel Arteta's side have emerged as Europe's preeminent force at corners and free-kicks thanks to their set-piece guru Nicolas Jover.
Having worked with Arteta during their time on Pep Guardiola's Manchester City coaching staff, Jover was persuaded to follow his friend to Arsenal in 2021.
Jover's clever schemes have been the unheralded secret of Arsenal's success – until this season when their exquisite execution finally became obvious to overwhelmed opponents.
The Gunners have scored 44 goals from set-pieces (excluding penalties) since Jover's arrival, including 25 in the Premier League since the start of last season.
That is the most of any side in the English top-flight in that period, with 19 of those goals coming from corners, including Gabriel Magalhaes' crucial header in the 2-2 draw at title rivals Manchester City.
Jover's importance to Arsenal was laid bare when Arteta smothered him in a bear hug on the touchline when another Gabriel header from a corner sealed a vital 1-0 win at Tottenham earlier this season.
"In his field, in other fields, as a person, the relationship that we have, that's why I made a decision to bring him to City when I was there and then to Arsenal," Arteta said.
"Him and the staff, they have injected belief to the players that there are many ways to win football matches.
"It's a really powerful one and it's given us a lot. So a big compliment to all of them, for sure."
Jover has conjured up deceptive routines to both attack and defend from set-pieces.
The German-born 42-year-old's most successful creation sees the opposing goalkeeper put under pressure by a ring of Arsenal players while Gabriel times his run to meet a corner at the far post.
"Credit to Nico. I think he does an amazing job. We train a lot on it. You see it every week how important it is. Sometimes set-pieces decide a game. We are glad to have Nico," Arsenal forward Kai Havertz said.
'SET-PIECES ARE REALLY IMPORTANT'
In stark contrast to Arsenal's attention to detail in dead-ball situations, Paris Saint-Germain have stubbornly opted against focusing on set-pieces.
PSG boss Luis Enrique did not bring in a specialist when he was hired and the club reportedly work on attacking and defending set pieces only occasionally.
That has led to PSG routinely conceding from corners and free-kicks, a weakness that has Jover licking his lips in anticipation of exposing their flaws.
The French champions' curious attitude to set-pieces has left them vulnerable, much like Tottenham – serial victims of dead-ball mistakes whose boss Ange Postecoglou is one of the few Premier League managers yet to embrace the trend.
Champions Manchester City have benefitted from Guardiola's decision to promote Carlos Vicens from Under-18 coach to set-piece specialist in 2023.
City scored 21 times from set-pieces and conceded just once in their march to a fourth successive Premier League title last term.
"Today in modern football, set-pieces are really important," Guardiola said.
"We are preparing things in the corners like every team does. Someone had to come with the ideas, and we are going to do this so all credit to Carlos."
Brentford, who employed Jover for three years, were one of the earliest adopters of the set-piece revolution and Chelsea paid £750 000 ($1 million) to sign their dead-ball coach Bernardo Cueva in May.
Andreas Georgson recently joined Manchester United with set-piece schemes his primary task, while Austin MacPhee's routines helped Aston Villa reach the Champions League for the first time in 41 years.
Liverpool advertised for the position after Peter Krawietz's summer exit, their job application seeking a "tactical specialist" with "the ability to expertly coach both offensive and defensive set-piece strategies".
For now, there is no doubt Arsenal are leading the race to capitalise on the marginal gains that can decide a title race or make a European champion. PSG have been warned.