We last kicked off with a home defeat in 2014, when a Gylfi Sigurdsson-inspired Swansea City beat United in Louis van Gaal's first game as manager.
Former England worldwide Rooney is optimistic that Manchester United can get one or two more transfer deals over the line to add some more quality to Mourinho's squad.
Over at Sky Sports, pundits Charlie Nicholas, Phil Thompson, Matt Le Tissier and Paul Merson all tip City to finish top and Liverpool second.
"We might not be able to count on everyone who's been playing at the World Cup but everyone who has had a full pre-season is keen and eager to get going and hopefully we'll be in good form".
Manchester United lost 1-0 to Chelsea FC in the FA Cup final at Wembley last season.
City broke a number of records in 2017/18, with their Premier League points tally hitting the 100 mark in what was an unprecedented achievement.
'American Pickers' discover Aerosmith's van from 1970s in MA woods
Decades later, the van has been found by none other than the stars of History Channel's hit show " American Pickers ". Luckily for American Pickers , Phil was willing to part with the piece of music history found on his property.
"Before saying anything or doing anything, you want to observe and see if you can see the same mistakes as what we made previously", the centre-back told Sky Sports. "We've discussed that many times in Europe". "Nobody is consistent with 11 players".
Chelsea suffered the biggest shock of the season, finishing fifth just one year after winning the EPL title.
The deal, which is not yet finalised, is said to please all three parties as the 24-year-old is guaranteed regular game time, Chelsea will have another option for their midfield and Real do not permanently lose out on a player they still rate highly.
As the news emerged, Chelsea fans on Twitter erupted with joy.
Yet, based on the World Cup performances of Golden Boot victor Harry Kane, Hugo Lloris and Christian Eriksen among others, there is still plenty for Mauricio Pochettino to look forward to.