Sporting competition at the elite level is more often than not decided by the finest of margins and coaches will consider all the tools at their disposal in pursuit of glory.
That means stuff like focused training programmes, forensic analysis of opponents and getting nutrition right, but there is another, more abstract area that can be delved into as well: mind games.
It is a murky realm and those coaches who visit it can find navigating the terrain to be risky business, but every now and then it will produce results.
Goal takes a look at mind games in football and the coaches who play them.
What are mind games in football?
The term 'mind games' in football refers to a form of psychological conflict whereby a manager attempts to gain an edge over a rival by disrupting their focus ahead of a game.
That edge can be achieved through verbal volleys and proverbial tongue-lashings or, indeed, by physical action, though using words is a much safer option in terms of avoiding punishment.
Press conferences and post-match interviews are often fertile ground for managers to indulge in such mental warfare as they have a captive audience, so their barbs have a greater chance of landing.
Getting into the head of an opponent has long been a tactic in football and it isn't confined to managers, with players also partaking in the practice, often doing so on the pitch.
However, in the 21st century, it is notable that much more attention is being paid to psychology in sport and some clubs have even employed dedicated psychologists to look after the mental wellbeing of their players.
Remarking on the use of a sports psychologist at Liverpool in November 2019, Jurgen Klopp said: "I think around about 20, 25 years ago there were no goalie coaches in football and the head coach did the goalie training by himself. You had no athletic coaches, it was all our job pretty much. So, the teams around the team became bigger. The next thing was, of course, with psychology."
As the German coach explains, the introduction of a professional dedicated to mental matters is part of the continued pursuit of earning small advantages, wherever they may be found.
“What he is doing with the players, I am not involved," Klopp said. "I have my part to do with the boys and do that like I did it before. It's just an add-on for all the things we try to deliver. We try to make sure the boys are in the best hands."
Which football managers play mind games?
Jose Mourinho
Of all the managers in modern-day football, Jose Mourinho is probably the one most associated with playing mind games.
The self-anointed 'Special One' cultivated a particularly sardonic persona during the early stage of his career and has reanimated that aspect of his character periodically when things begin stacking up against him.
As Real Madrid head coach, Mourinho took the mind game level up to 11 in the battle for supremacy with Barcelona and Pep Guardiola, even poking Barca assistant coach Tito Vilanova in the eye during a sideline kerfuffle. “It’s not important how we play," he said during that time. "If you have a Ferrari and I have a small car, to beat you in a race I have to break your wheel or put sugar in your tank.”
His behaviour was widely denounced and he wasn't particularly loved, but the Portuguese ultimately broke Barcelona's grip on La Liga by winning it in 2011-12.
Mourinho's mind games have been directed at many people over the years. He branded Arsene Wenger "a specialist in failure" and a "voyeur", for example.
Pep Guardiola
Having found success at Barcelona, Bayern Munich and Manchester City, Pep Guardiola knows what it takes to tactically propel a team to the top, but he is no saint and he too has indulged in mind games.
During his time as Barcelona boss, Guardiola was drawn into a battle of wits by none other than then-Real Madrid manager Mourinho and delivered the withering verdict that Mourinho could have his own "personal Champions League outside of the field".
While the Catalan coach often presents a cool exterior during press conferences, beneath lies a fiery temperament and as manager of Bayern Munich he famously and sternly commanded a Guardian journalist to look at him when speaking with him.
As manager of Manchester City, Guardiola's main rivals have been Liverpool and they have rarely been far from his thoughts during press conferences - whether it be casting doubt over Sadio Mane's integrity by suggesting that he likes to dive, or by criticising referees.
Alex Ferguson
Alex Ferguson led Manchester United to Premier League dominance during the 1990s into the 2000s and along the way he mastered the dark art of mind games.
Comments made by Ferguson regarding fixtures favouring rivals famously provoked Rafa Benitez during the 2008-09 season, when the Spaniard's Liverpool team were out in front in the race for the title.
Benitez surprised the Premier League-watching public when he dispensed with his cool exterior to deliver a lengthy tirade addressing "facts".
"I was surprised by what has been said, but maybe they [Manchester United] are nervous because we are at the top of the table," said the Spanish coach. "But I want to talk about facts. I want to be clear, I do not want to play mind games too early, although they seem to want to start."
Despite protestations to the contrary, Liverpool were clearly unnerved and eventually beaten to the title by Ferguson's Manchester United in a capitulation that was reminiscent of Newcastle United's collapse in the 1995-96 campaign, when Ferguson got into the head of Kevin Keegan.
On that occasion, having cast aspersions on Newcastle's opponents in the title run-in by suggesting they might not be fully committed, Ferguson drew out an angry rant from Keegan, live on TV, in which the former Magpies boss uttered the line, "I will love it if we beat them!"
Unfortunately for Keegan, however, they didn't beat the Red Devils to the title and Ferguson had the last laugh.