Go back two weeks and the gap between them was five points. Some thought it would be stretched. Now Tottenham have drawn level with Manchester United.
The narrative of a title race being an all-Mancunian affair has to be ripped up. Spurs have acquired momentum as United have lost it. Their meeting today becomes season-defining.
So, too, have been their recent games. This forms the last in a trilogy involving Liverpool. United defended against the Merseysiders and secured a stalemate away. Tottenham attacked and blew them away 4-1 at Wembley.
It may highlight how Mauricio Pochettino's football is more adventurous than Jose Mourinho's. The Argentinian is progressive and the Portuguese, after United's prolific start to the season, has been branded regressive.
Yet opposites have a similar aim: to secure a response. United need to get back on track after Saturday's shock 2-1 defeat by Huddersfield, when Mourinho felt their attitude was the poorest since he has been at the club.
Spurs were looking relentless until they lost a two-goal lead and were knocked out of the League Cup by West Ham.
But that was with a weakened team. In the senior competitions, at least, Tottenham have coped better with absences than United, who have lost fluency without Paul Pogba and ungainly effectiveness without Marouane Fellaini.
It has been compounded by a loss of form among their attacking midfielders, Juan Mata and Henrikh Mkhitaryan in particular.
Their Tottenham counterparts, Christian Eriksen, Dele Alli and Son Heung Min, have been excellent of late. They may need to be: Harry Kane is out and, while Spurs beat Manchester City without him last season, he could be the one player they cannot afford to lose.
Minus Kane, it gives Romelu Lukaku a chance to reclaim the advantage in the shoot-out for the Premier League's Golden Boot.
The clash of the defensive midfielders, Eric Dier and Nemanja Matic, will be a man Mourinho tried to sign against one he did.
The tactical contest would seem to pit contrasting philosophies against each other.
Pochettino is indelibly associated with a high-paced pressing game. Yet he drew against Real Madrid and beat Liverpool by switching tack, letting their opponents have more of the ball and launching devastating breaks.
Mourinho's fondness for counter-attacking football is well known, so it may be a question of who can lay a trap that the other will fall into. Because the scenario seems to suit both. United have one of two 100 per cent home records in the division, Tottenham one of two impeccable away records.
The last time they won their opening four games on the road was in 1960, when they went on to become English champions.
If a repeat appears unlikely, this should determine who are City's closest rivals.
But if it is Spurs, the budget challengers, it would represent an indictment of Mourinho and United's big spending.
MANCHESTER UNITED V TOTTENHAM
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