Jose Mourinho and Ed Woodward finalised Manchester United's list of summer transfer targets in March. But only a few weeks later, the plans had to change.

Zlatan Ibrahimovic's knee ligament injury against Anderlecht in April forced a rethink.

Asked the following week whether the Swede's absence would mean a change of direction during the transfer window, the United manager accepted that it did.

Mourinho said: "Yes. Yes. Because if I don't have the players for a long period of time, obviously it affects."

It was the moment that interest in Antoine Griezmann began to cool, although, in the end, the France forward decided to stay at Atletico Madrid anyway after the Court of Arbitration for Sport upheld the Spanish side's transfer ban.

The problem United faced was finding a replacement for Ibrahimovic.

Mourinho usually prefers a strong, physical centre-forward to spearhead his team. But there are not that many about and even fewer available.

Bayern Munich did not want to sell Robert Lewandowski and Tottenham Hotspur had no interest in negotiating over Harry Kane.

There were doubts about Alexandre Lacazette after mixed scouting reports from France while Andrea Belotti has only had one standout season for Torino.

It left two players Mourinho knows well: Alvaro Morata and Romelu Lukaku.

In the back-and-forth between intermediaries early on, it became apparent to United officials that Morata should be significantly cheaper than Lukaku.

Morata scored 20 goals in 43 games for Real Madrid last season but was only ever considered a backup and began the Champions League final on the bench.

Lukaku, meanwhile, was Everton's main man.

Only Harry Kane scored more than Romelu Lukaku's 25 Premier League goals last season. PAUL ELLIS/AFP/Getty Images

United were also acutely aware as early as April that Everton, boosted by Farhad Moshiri's investment, would be major players in the transfer market and would not want to lose their star striker on the cheap during their statement summer.

There was also a point in June when it looked likely Lukaku would return to Chelsea.

Antonio Conte had reportedly text-messaged Diego Costa to tell the striker he was no longer in his plans and the Belgian's return to Stamford Bridge seemed like a perfect fit.

Despite Morata's apparent willingness to move to Old Trafford, negotiations with Real Madrid hit a brick wall over the fee.

The Spanish giants' asking price of €90 million was well above United's valuation and a deal that had, at one stage, appeared the more straightforward of the two began to look far more complicated.

Even after Morata, his father, Alfonso, and his agent, Juanma Lopez, met Real Madrid officials at the Bernabeu on Monday, Florentino Perez refused to budge.

In 2014, Perez was well aware that Louis van Gaal wanted Angel Di Maria. United were quoted £60m and, despite months of haggling, eventually paid £59.7m.

With Mourinho's need for a particular type of striker well-known, as well as his appreciation for Morata, Real Madrid had hoped to cash in.

Real Madrid forward Alvaro Morata had looked destined to join Manchester United. FILIPPO MONTEFORTE/AFP/Getty Images

But United, with encouragement from agent Mino Raiola, had continued their talks with Everton for Lukaku.

The deal to take Wayne Rooney back to Goodison Park has been kept separate, with United keen to make sure their captain and record goal scorer is not ushered out the door as a makeweight in a bigger transfer.

But Everton's interest in Rooney gave United executive vice chairman Ed Woodward and head of corporate finance Matt Judge a bargaining chip.

Eventually Everton were convinced to reach a compromise over Lukaku and agree on a price that was lower than what Real Madrid wanted from Morata.

The fee for Lukaku is £75m, a price tag United officials do not think is unreasonable for a player who scored more Premier League goals than Sergio Aguero, Alexis Sanchez and Costa last season.

The 24-year-old has netted 71 goals in 133 games for Everton since signing permanently in 2014. Morata has scored 47 times in 136 games during the same period.

Morata's Champions League experience appealed to Mourinho. But, then, Lukaku is proven in the Premier League.

Sources have told ESPN FC that up until Thursday morning, Morata thought he would, eventually, sign for United.

His agent was said to be "shocked" when he was told over the phone that United had agreed a fee for Lukaku and had immediately ended talks with Madrid.

Chelsea tried to hijack the Lukaku deal on Friday, offering to match United's offer but not Raiola's fee. It was, though, not much more than a PR stunt in an attempt to save face having been beaten to their key summer target. United were always convinced they had got their man, and on Saturday were in a position to formally announce they had an agreement with Everton.

Mourinho began the summer needing a striker to fill the void left by Ibrahimovic. Woodward was determined that United would not be held to ransom again. Lukaku, meanwhile, wanted to play in the Champions League. In the end, they all got what they wanted.