Given the immense quality of the Manchester City squad, on any given matchday there is surely no end to the selection dilemmas pinging around inside Pep Guardiola's brain.
Which two of his five senior centre-backs should get the nod? Should Ilkay Gundogan or Bernardo Silva partner Kevin de Bruyne in attacking midfield? Which wide players are best equipped to beat a specific opponent? There must be no end to his self-questioning.
However, when City return to Premier League action on December 28 away at Leeds United, there could be a fresh dilemma that not even Guardiola was expecting to encounter.
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Julian Alvarez has enjoyed an excellent World Cup with Argentine, and now having seemingly established himself in the Albiceleste XI, it could get even better.
City's 22-year-old attacker went into the World Cup having been assigned the number nine shirt, but it was Inter Milan striker Lautaro Martinez who started Argentina's opening two group games in his place.
After making a positive impact off the bench in his side's crucial 2-0 win against Mexico, Alvarez was handed his first World Cup start by Lionel Scaloni in the 2-0 defeat of Poland. Alvarez buried a superb strike into the top corner to put Argentina 2-0 and help secure the spot in the last-16 as group winners.
He kept his place for the last-16 tie with Australia, and once again he scored a crucial second goal for his team. Leading an intense press, Alvarez pounced when Rodrigo de Paul robbed the Australian goalkeeper of the ball and coolly slotted home. That Australia pulled a goal back with 20 minutes left to play made his contribution all the more important.
Alvarez is likely to keep his starting gig when Argentina take on the Netherlands in Friday night's quarter-final. But even if he doesn't score another goal this tournament, he has given Guardiola food for thought.
So far in his City career Alvarez has been the clear second striking option behind Erling Haaland. Five of Alvarez's seven City starts in all competitions have come when Haaland has been injured or rested; two, both in the Champions League, saw the Argentine play slightly behind his colleague as a second striker.
Guardiola needs no reminding of Alvarez's quality - on multiple occasions this season he has heaped praise on a youngster who has made nine direct goal contributions in 20 outings. But add to that Alvarez's World Cup antics while playing alongside Lionel Messi - the player Guardiola holds head and shoulders above the rest - and the evidence supporting Alvarez's case for more starts to stack up.
The deeper Argentina go in the World Cup the more unlikely it becomes that Alvarez will return to City in time to feature in the Carabao Cup clash with Liverpool - scheduled for four days after the World Cup final - or the trip to Leeds.
But should he return slightly sooner, in good form and match sharp, then he could well get the nod over Haaland. The Norwegian lacked fitness in City's final few matches before the World Cup, and is currently training on his own as part of City's week-long training trip to Abu Dhabi.
Whatever happens, one thing is certain: Alvarez has proved beyond doubt that he can mix it with the best and perform on the biggest stages. That's good for both him and City, but it might cause Guardiola a few more headaches.
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