In the dying embers of the FA Cup semi-final, Erik ten Hag looked over to his bench to see what he could change. Manchester United were lifeless and leggy for much of the match against Brighton, yet the manager was reluctant to bring on fresh legs just for the sake of it.
Anthony Martial only lasted until the 85th minute because, quite frankly, there were no other viable options at United's disposal. Antony was replaced in added time when it became abundantly clear he would not be the match-winner they had hoped for.
Taking off Bruno Fernandes and replacing him with Wout Weghorst looked akin to Louis van Gaal's infamous decision to replace Juan Mata with Nick Powell in their Champions League exit to Wolfsburg back in 2015. This time, the gamble paid off.
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United's penalty shootout success vindicated those decisions, though the underlying worry is that they will most likely need to offer a lot more when they face fierce rivals Man City in the final.
It was a day in which they were crying out for a gamechanger from the bench. Someone to run at a tired defence, with enterprise and energy. They needed Alejandro Garnacho.
The 18-year-old is still an incredibly raw talent but has showcased this season he has the tenacity and talent to grab a game by the scruff of the neck. Garnacho registered four goals and five assists in 29 appearances prior to his ankle injury last month. He also boasts an impressive four goals in four appearances for Argentina's U20s.
While he still has a lot of work to do, his youthful innocence and pure persistence make him a thorn in the side of many opposition defences. Most players drop their heads when they lose possession or are struggling to find a way past defenders, but it is testament to the Argentine teenager that he very rarely does.
Indeed, he did just that in United's win over Man City back in January, with a sensational substitute display that turned the game in his side's favour.
Garnacho was introduced in the final 20 minutes of that match and would set-up the winning goal through his sheer persistence down the left flank. His first cross into the box was blocked, but he collected the ball again, turned Nathan Ake and squared back for Marcus Rashford to fire in the winner.
It is that game-changing ability that United will need at Wembley, even if it means ending his dreams of representing Argentina at the U20 World Cup.
Argentina want Garnacho to play a part in the competition, which starts on May 20, with coach Javier Mascherano understood to have held talks in an attempt to convince United to release him.
Garnacho views the U20 World Cup as another opportunity to prove his worth at international level, as he looks to eventually earn a permanent promotion to the senior set-up and play a key role for them in the years ahead.
The issue is that United don't have any interest in doing that, and while they recognise it would be a brilliant opportunity for the teenager, they also see him playing an important role for them between now and the end of the season.
FIFA rules say clubs must release players when they are called up to their countries, but this only applies during designated international windows, and won't apply to the U20 World Cup.
If United had lost at the weekend, there would have been a greater argument to let him go, given he'd have only missed the final three matches of the Premier League season, by which time a top-four finish could already be secured.
However, the scheduling of the FA Cup final for after the season has ended completely changes the dynamic. It is not only the chance of winning another trophy; it is the possibility of crushing City's dreams of a treble.
Argentina face Uzbekistan in their opening group game on May 20, followed by games against Guatemala and New Zealand. If they make it to the quarter-finals, that game would take place on the same weekend as the FA Cup final.
United need to be selfish and put their own interests ahead of those of their talented teenager, and it could well benefit both parties if indeed he is given the chance to shine during the Wembley showpiece.
Garnacho has already been a game-changer once against Man City this year; United need him to do it again.
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