Lowdown: United improved in virtually every respect – points, goals, wins, league position – last season, but losing to all three promoted clubs, finishing 19 points behind their local rivals and failing to perform in both the FA Cup final and their Champions League exit.
Closing the gap will be difficult: more difficult, Jose Mourinho has suggested, because of their travails in the transfer market, though Diogo Dalot could be the future right-back and Fred has arrived as a replacement for the retired Michael Carrick.
But the extra defender and winger the manager wanted have not yet arrived and Mourinho’s mood feels a problem.
Key player: Paul Pogba – France's World Cup win showed the player Pogba can be and the reason United paid a then world-record fee for his services. If he can ally tactical discipline with surging runs, he will both please Mourinho and answer questions about United's best formation.
Manager: Jose Mourinho – Has cut a bad-tempered figure on United's pre-season tour of the United States with his frustrations about a lack of transfers and with certain players offering reminders Mourinho tends to suffer from third-season syndrome. It can be when things start to go wrong for him. Will this be different?
Talking point: Can Alexis Sanchez deliver? In his last full season at Arsenal, the Chilean was so potent he ranked among the best players in England. In his first few months at Old Trafford, he scored three goals in 18 games.
Rather than being a short cut to success, as he seemed the case, he struggled to settle and created problems with Marcus Rashford and Anthony Martial marginalised and Sanchez and Pogba struggling to coexist.
The challenge for Mourinho is to get Sanchez to produce the form that brought him 30 goals for Arsenal in 2016 and to gel with Pogba, Lukaku and co.