There is an inter-club rivalry that has dominated the build-up to the World Cup final. Qatar's showpiece is being headlined by the two biggest stars of its club vehicle, Paris Saint-Germain, and it's hard to divert the build-up to today's game away from the head-to-head between Lionel Messi and Kylian Mbappe.
But since 1990, the first World Cup final to feature teammates on different sides, it has become a regular occurrence, and including PSG there are five clubs with a foot in the France and Argentina camp. For the first time, Manchester United fans will watch a World Cup final with split loyalties.
Tottenham, Atletico Madrid and Juventus also have representatives on both sides of the divide and as the game becomes more global, the rivalries on the biggest stage are likely to become more colloquial. At each of those five clubs at least one player will return a victor and one a loser from the biggest game on the planet. There could be some awkward exchanges at training grounds over Christmas.
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United have never before had two players on opposing sides in a World Cup final and if Raphael Varane and Lisandro Martinez both play, it will be another first. No United player has ever played in a losing cause in a World Cup final before.
Mikael Silvestre and Louis Saha were both in the France squad that lost to Italy on penalties in the 2006 final, but neither got on the pitch. On the other hand, one of Varane or Martinez will become the fifth player representing United to win the World Cup, after Bobby Charlton, Nobby Stiles, John Connelly and Paul Pogba, the first three of those back in 1966.
United are guaranteed to have a World Cup winner in 2018 and 2022 and you'd get short odds they'll have a representative on the winning side in 2026 as well, especially with the Premier League's elite attracting the best players in the world at the moment.
United's history with modern World Cup finals is not as glamorous as you might expect, certainly compared to their European rivals and maybe even their domestic ones, given the club stand as one of the biggest in the world. Arsenal have had six World Cup winners since 1998, Chelsea three since 2014 and Liverpool had two in 2010.
World Cups have often been a precursor to disappointment for United. They signed Marcos Rojo a month after he played in the 2014 final and Kleberson a year after he helped Brazil win the 2002 tournament. Fabien Barthez played in two World Cup finals, the first was two years before he joined and the second two years after he left.
Either Varane or Martinez will be triumphant in Qatar today, but the extent of their involvement remains unclear. Varane has started five of France's six games since recovering from an injury he picked up playing for United, but in the days leading up to the final he has been laid low by a virus that has swept through the squad.
Martinez has started twice for Argentina and come off the bench in three more games, but he looks to be second choice for Lionel Scaloni behind Nicolas Otamendi, a turn of events that would astonish regular football watchers in Manchester, but one that is hard to argue against given Argentina's excellent defence.
Like Mbappe and Messi, Varane and Martinez will return to their club after Sunday and have to restart a close partnership. They have started nine games together as Ten Hag's first-choice defensive partnership, with United losing just once.
There is no doubt they are the best central defensive pairing the club have had for a long time and they've come together for barely £100million. That's a bargain when you consider that they spent £80m on Harry Maguire.
They will be enemies in Qatar today and will make United history in the process. But in the short-term and the long-term they are vital to Ten Hag's Old Trafford project.
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