At the second time of asking, Manchester City got their man. Just as he had at Barcelona, Pep Guardiola signed Alexis Sanchez. He'd been prepared to wait, but after a deal broke down in summer 2017, Sanchez eventually arrived in January.

Only he didn’t – or not at the Etihad Stadium, anyway. Instead, his second Manchester derby will come against his long-time suitors on Sunday. Sanchez set up Chris Smalling’s winner for Manchester United in the first, delaying City’s coronation as champions by a week, but it's impossible to argue that his time at Old Trafford has been a success.

Partly because of the aforementioned derby, he's been outscored by Smalling in the Premier League in 2018. A footballer who managed a goal every 170 minutes in the division for Arsenal averages one every 495 for United. So far this term, he trails James Tarkowski, Shane Duffy and Harry Maguire in the scoring stakes. There have been occasional uplifting days – Newcastle, Bournemouth – but many more times Sanchez has looked disconsolate and purposeless. He has seemed an idealist stripped of his ideal, denied his dream move and discovering the consolation prize of a transfer to United is not especially consoling.

No swaps

The consequences at Old Trafford have been impossible to ignore. Marcus Rashford and, particularly, Anthony Martial suffered when the newcomer was given preferential treatment. The Frenchman could have left; instead, he's reshaped the pecking order with a sudden surge of form in recent weeks.

Sanchez now feels like football’s most expensive substitute; United hamstrung for years by a salary they probably can't shift, their squad left lopsided when a man equally adept on the right - Henrikh Mkhitaryan - departed and the Chilean joined the logjam of would-be left wingers.

Yet the knock-on effect of that Sanchez saga at the Etihad may be more interesting. Perhaps it dates back to last summer, when Arsenal proposed including Raheem Sterling in a swap deal. City must be relieved, and can feel vindicated, that their preference was for a cash-only move: since then, only Mohamed Salah has been involved in more Premier League goals than Sterling.

His transformation into talisman and finisher has been a testament to Pep Guardiola’s coaching prowess. No one delivered more decisive late goals than the Englishman last season, and it's safe to say that many of City’s records would have been left unbroken had he gone. If they did miss the man they didn't sign, it was arguably only in Europe: one theory was that, with a huge lead in the Premier League, City wanted Sanchez for their Champions League aspirations.

Disruptive

But the repercussions of January’s sudden volte-face are still considerable. City felt Sanchez’s proposed salary was prohibitively expensive, and that it could have had a knock-on effect when Kevin De Bruyne and Sterling came to renegotiate their contracts.

Instead it's United who have England’s biggest wage bill, and the burden on the budget who may be impossible to shift. Without Sanchez, City have felt less of a star vehicle. They've still spent huge sums, but the profile of the players they've signed makes it feels less a case of chequebook management with celebrity targets.

Riyad Mahrez was the immediate beneficiary, as the winger Guardiola instead recruited from Leicester. He has more league goals in his brief City career than Sanchez has in his lengthier time at United. The Algerian’s Wembley winner against Tottenham gives him a distinction the Chilean lacks – a decider against an elite side – even if, on the debit side, his skied penalty at Anfield cost him another.

But Mahrez’s preference for playing on the right has brought Sterling different duties. Guardiola’s game plan for the bigger matches has entailed picking the newcomer and shifting Sterling to the left; this, presumably, would have been Sanchez’s role, as the inverted winger. If Leroy Sané was deemed indispensable to add width last season, Benjamin Mendy’s return to fitness has meant the full-back can stretch the game and a right-footed left-winger can cut in to shoot.

Sané has been in and out of the City side this season. Had Sanchez arrived, it's tempting to wonder if he would have become City’s Martial, starved of opportunity, while Sterling had rather less competition on the right. Sergio Aguero, too, may have suffered. Versatile players always have an appeal to inveterate tinkerers like Guardiola. Specialist strikers can look like endangered species in his sides and, at times, Aguero has been benched for those who press more naturally or who better resemble false nines. Sanchez would have been a threat.

Flawed recruitment

Instead, Aguero has reigned supreme this season. Gabriel Jesus, amid a loss of confidence and goalscoring form, has become the anti-Sterling who hasn't yet kicked on under Guardiola. Aguero has adjusted to the new demands without losing his timeless knack for scoring. Yet perhaps with a rival, a man who has been benched for two of the bigger games of the Catalan’s reign – away at Barcelona in 2016 and last December’s Manchester derby – may have been given further votes of no confidence.

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Not on current form, however. The great unknown is whether City would have got the Sanchez that Arsenal savoured in 2016/17, or the one who has struggled with United in 2018. He could have been a distraction on Guardiola’s bench by now; an underachieving indictment of a policy of raiding rivals to weaken them. If City saw signs of decline, they were more perceptive than United.

If United thought they'd got one over on their neighbours, they were wrong. And if Sanchez was supposed to alter the balance of power between local rivals, instead the gap has swelled since he joined United.

Last season’s most stunning signing was the coup that wasn’t; the symbol of how United lost their way; the example of how it isn't a good idea to buy someone simply to stop your enemies having him.

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