As always, the fans of the handsome game are in for their share of ups and downs over the next nine months. But for City, anything less would be a disappointment.
Speaking at his press conference ahead of the Premier League opener between Manchester United and Leicester on Friday, Mourinho was in a defensive mood about the criticism his United team got for finishing behind a massive 19 points behind Pep Guardiola's record-breaking City side.
They really look like they mean business, spending an terrible lot in the transfer window.
Mahrez is one of the best wingers in the Premier League, and that City signed the 27-year-old this summer underlines his quality.
Having taken advice from former Arsenal midfielder Gilberto Silva regarding the demands of the Premier League, a quick transition into English football could help United as they seek a first title since 2013.
One of Mourinho's most trusted lieutenants Nemanja Matic will miss the start of the season due to surgery on an abdominal injury, while Eric Bailly and Ander Herrera are also doubts after picking up knocks in United's final pre-season friendly defeat by Bayern Munich. Striker Harry Kane committed his future to Tottenham before heading to the 2018 World Cup in Russian Federation and finishing as the top-scorer as England reached the semi-finals.More news: Turkish president: United States set deadline to release detained pastor
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The playmaker was a fundamental part of Sarri's midfield in Naples, dictating their tempo as they pushed Juventus all the way in last season's Serie A title race.
And if Klopp does not deliver a trophy this season and they don't progress into the latter rounds of the Champions League, then he may find it hard to hold on to his job.
Wanderers, who won the Championship title last season, have strengthened their squad with eight new players over the summer.
It will seem odd not see the unmistakable figure of Arsene Wenger on the touchline for Arsenal. It will be a tough task for both managers to make their marks in their first seasons. "That's reversing the trend we've seen in the last few years".
Instead, the Portuguese's mood has been further soured by seeing another fierce rival Liverpool steal a march with a £170-million ($220 million) splurge on new signings. Cardiff will likely struggle up a division but Fulham, too, could punch above its weight.
The English Premier League's (EPL) transfer window closed on August 9 with more than 1 billion euros spent by the teams.