An absorbing if not classic Manchester City victory made them the first team in the history of top-flight football to win a 14th consecutive league game in the same season, ending in the process United’s proud, club record-equalling run of 40 consecutive home matches without defeat.
That sequence dated back, of course, to Pep Guardiola’s victory in the corresponding derby fixture last September.
But much has happened to both teams in the intervening 15 months and Jose Mourinho was saying nothing revelatory when he declared before kick-off that both his team and Guardiola’s are better outfits than they were when they last met in the league at Old Trafford.
That fact, which has led to the two rivals occupying the top places in the Premier League, is what gave this derby some added impetus.
For the first time since Sir Alex Ferguson put away his tea cups and retired to leave those noisy neighbours to it, here was a derby game with the potential for real impact on the Premier League’s title race.
Certainly an Old Trafford which all too often struggles to generate the big-match atmosphere Mourinho calls for did not need telling twice that this was a game that really, truly mattered, and the visiting support naturally reflected the same.
As the first half wore on, those City fans took great delight in taunting their rivals with chants of “Park the bus”, although in defence of United’s defence, they had little option as City simply refused to give up the ball.
It led to an inevitable opening goal that stunned the majority of the capacity crowd although, to their credit, United’s response was swift – an Anthony Martial attack, a Marcus Rashford equaliser – and Old Trafford erupted again.
The two managers offered a similar study in contrasting styles. Mourinho, at pains to be seen to be on his best behaviour, prowled the technical area, erupting on a couple of occasions at the fourth official when he simply could not help himself.
In stark contrast, Guardiola turned in his usual impression of an Energizer Bunny, a whirling dervish of energy and emotion on the sideline who looks as if he might be about to suffer a hernia, or worse, with every over-hit ball and badly-judged pass made by his players.
When Vincent Kompany pumped two hopeful long passes in quick succession half the length of the field and directly into touch for United goalkicks, it appeared that Guardiola might need to be sedated for his own well-being.
But that would have meant the Catalan missing one of his finest hours as City manager, not to mention one which places him firmly in the English football record books.
Arsenal won 14 straight top-flight games, but over two separate seasons, while in the history of the professional sport in this country only three other clubs have compiled that sort of commanding sequence – United in 1904-05, Bristol City a season later, and Preston in 1950-51, for those keeping score at home.
All those teams pulled off that run in the second tier of English football, making the achievement of this Guardiola side unparalleled in the game.
That statistic, of course, will not even have registered with the demanding, perfectionist in charge of the league leaders. The only number that will matter to him is 11 – the points gap they now boast over United and any other challengers to the title.
The irresistible force was resisted at Old Trafford and Guardiola and City now remain peerless, the Premier League’s immovable object.