‘Not sure who picked it but that’s a commercially-driven decision if ever there was one!’ whined Yeovil Town’s official Twitter account after Alexis Sanchez was named man of the match towards the end of Manchester United’s 4-0 FA Cup win on Friday night. The decision was Martin Keown’s, and rather than anything commercial, it was perhaps more of a gesture to recover some credibility after the BBC pundit had spent a fair portion of the previous 90 minutes referring to Sanchez with the kind of bitterness that you might get from one of Jose Mourinho’s juicy oranges.

However resentful Keown may be of Sanchez’s decision to join United instead of City, and despite whatever other suggestions Yeovil’s social media guru may have offered, it was the right choice. Of course it was. Sanchez was the best player on the bumpy pitch, offering just a taste of what United supporters can expect from ‘the biggest mercenary in football’.

The first answer to one of the week’s most-asked questions was ‘on the left’. Sanchez flanked Marcus Rashford, who was employed through the middle, and offered the kind of effervescent display of imagination, speed and penetration that, despite their attacking riches, United too often lack.

Though he roamed inside to provide a link between Rashford and the deeper midfield three, Sanchez did not wander too far from his post. Still, no-one was more involved, with the Chilean having a team joint-high of 97 touches – the same amount as Ander Herrera despite playing 20 minutes less than the Spanish midfielder – while six key passes, five more than any other starter, suggests his team-mates are going to reap the benefits of United’s investment.

Herrera, who celebrated his 150th United appearance by scoring their second goal, had Sanchez to thank for laying it on. With one assist already notched up, Sanchez took the ball from Juan Mata and led the counter charge, with Herrera pulling off to his left and Rashford steaming up through the resulting channel. The most obvious pass was to Rashford but Sanchez reversed his ball through his dust and to the feet of Herrera, who was able to take a touch and measure his finish.

Sanchez’s intelligence was not lost on Mourinho. “His choice for the second goal is a choice that a player like Marcus Rashford is too nervous to make that kind of decision. He brings maturity and class.”

That was no dig at Rashford. It was just that he was in attendance while Sanchez was putting on his clinic. The sentiment would be no less applicable if Mourinho was referring to Anthony Martial or Romelu Lukaku.

Sanchez’s arrival offers a fantastic learning opportunity for Rashford and Martial. Despite concerns being raised about what his signing does for their prospects, both have far more to gain from the presence of the 29-year-old. It was the same, especially for Rashford, when Zlatan Ibrahimovic was recruited but when he has had the opportunity to play as centre-forward, the England youngster has shown that his development has only been furthered. With the closest possible view of Sanchez everyday, Rashford’s creative capacity will only become more nuanced.

The same goes for United’s forward line as a whole. It does not lack pace, nor power, but while speed and the capacity to thrill has always been prevalent in their attack, save for a couple of laborious years under Louis van Gaal, what has been absent too often is timing, finesse and perhaps a touch of unpredictability. Mata offers an element of balance on the right, but Henrikh Mkhitaryan was too rarely able to tune into the same frequency as his all-action team-mates.

In 71 minutes at Yeovil and, more tellingly, three and a half seasons at Arsenal, Sanchez has demonstrated that not only can he maintain United’s tempo, the new arrival can dictate it. So often in 18 months, Mourinho has been exasperated by his side when they keep hitting defensive walls but now, when the Stretford End defaults to cries of ‘attack, attack, attack’ despite the intent being plainly evident, Sanchez can plot routes around and through even the most resilient rearguards.

He is barely three-quarters of a match into his United career but, as Mourinho said, there are no doubts over Sanchez’s suitability to this team. The only question mark, especially if his wavelength matches that of Paul Pogba, is how far last night’s debutant can take them.

Ian Watson