It's been a relatively peaceful few years between the rivals but Mourinho's return suggests tensions will be back
It hasn't taken long for the first stirrings of tension to raise their heads.
Of course, press questions don't help that and Arsene Wenger is generally open to answering them.
The question posed to the Arsenal manager in the lead up to the Saturday lunchtime kick-off between Manchester United and Arsenal was whether he would shake the hand of opposite number Jose Mourinho.
His response was thus: "I will respect the ritual so important in the Premier League."
Needless to say, the fact it even had to be asked is a sign of the professional enmity between the pair and the many Mourinho attempts at trying to take his rival down a peg or two.
The "Specialist in Failure" dig is still fresh in the mind, although his previous half-season at Chelsea and a tough start to his Man United management means Mourinho has had a taste of that.
It's a rivalry that should feed into the one that has long existed between United and Arsenal but has been relatively dormant in terms of tensions for the past few seasons.
Arsenal manager Arsene Wenger (right) looks on as Aaron Ramsey is shown the yellow card by Craig Pawson during the Barclays Premier League match at Old Trafford, Manchester. Picture by Martin Rickett PA Archive/PA Images
The encounters during the Alex Ferguson era peaked with pizzagate AKA the Battle of Buffet in October 2004 as the then-United boss tried to get one over a team that Wenger had just guided to Invincible status.
More often than not, the two clubs had to finish above each other to win the Premier League at a time when other rivals including Liverpool tended to be further behind.
With Arsenal becoming merely a perennial Top Four club rather than a true title challenger during the latter end of Ferguson's reign, the rivalry between both clubs became less heated, with the sting taken out.
Other rivalries took on preeminence, particularly with the rise of "Noisy Neighbours" Manchester City to prominence.
And neither of Fergie's successors - David Moyes and Louis van Gaal - fed into the rivalry with Arsenal or any other clubs for that matter as they chose to be more respectful and had little to no personal beef with any managers or clubs.
Mourinho's past when it comes to his relationship with Wenger and behaviour such as his brief disagreement with Chelsea manager Antonio Conte in October indicates that a little bit of venom could be injected back into the rivalry that has become like any other big game - even if it isn't fully apparent before Saturday's fixture.
Unlike almost any other time that the Portuguese coach has been in England, he goes into the game with a buoyant Wenger looking down on him from a higher placing in the table.
Indeed, the Gunners have been perched above United ever since Ferguson left and the gap is such this season that a rebuilding United will remain three points behind Arsenal even with a home win.
Given Mourinho's presence and Wenger's a little further along the touchline, there is a little bit more than three points at stake at Old Trafford which adds even more intrigue to the fixture.