Pep Guardiola wanted a new centre-back in 2018, and one who possessed a very specific quality. Nicolas Otamendi, Vincent Kompany and John Stones formed the heart of his defence at the time, but none of those players were left-footed.
The Spanish coach believed in a means of attacking which involved switching the play from one side of the pitch to the other. "Invite the opponent to press. You have the ball on one side to finish on the other," he said.
Fielding a left-footed centre-back would open up opportunities for Manchester City's attack. Not only would it aid build-up from the back, but it would allow the likes of Riyad Mahrez to benefit from one-on-one situations after being found by long diagonal passes.
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Aymeric Laporte was the man who was eventually identified as the club's top target, moving to the Etihad from Athletic Bilbao for a transfer fee of £57m.
"It’s so important to have a left-footed central defender," said Guardiola after the move was confirmed. "He helps us to make our build-up and when the ball comes from the right, he immediately controls to the left and plays it to Leroy [Sane] - that is quicker than we would play with a right-footer in that position."
Eighteen months later, Nathan Ake joined City from Bournemouth for £41m. Quality is undeniably important but in addition to that, the Dutch centre-back was another left-footed option.
Mikel Arteta was a part of Guardiola's journey in Manchester, operating as his assistant for a number of years. When he left to take over at Arsenal, he also showcased an intent on bringing in left-footed central defenders.
His first signing at the Emirates was Pablo Mari on loan for that very reason, before the Gunners signed Gabriel Magalhaes from Lille six months later, another left-footer.
Footedness is a trait which some coaches value more than others, but Guardiola in particular has always recognised it as important, which is curious considering Erik ten Hag's early moves at Old Trafford.
Having been appointed in the summer, the Dutch coach is looking to improve Manchester United as quickly as possible, with Lisandro Martinez announced as his third summer signing on Wednesday afternoon.
Crucially, Martinez is left-footed and he appears destined to be deployed as a centre-back at his new club, especially considering Harry Maguire has been moved to the right of United's two-man defensive pairing during pre-season, having previously played on the left.
Martinez arrives as the only left-footed centre-back in the United squad, unlike Maguire, Raphael Varane, Phil Jones, Eric Bailly and Victor Lindelof, who performed for the club on a regular basis last season.
Guardiola and Ten Hag once crossed paths at Bayern Munich, and although they will now be opponents in the Premier League, it seems the pair share similar ideas.
