The last time Tottenham Hotspur beat Manchester United twice in the league in one season was in 1989-90. Gary Lineker sealed a 1-0 win away at Old Trafford and then scored Tottenham's first in a 2-1 home win, with Paul Gascoigne grabbing the other.
The club's 3-2 away win this season was the first time they had beaten United in any competition since 2001. To beat them on Sunday would not only be notable historically, but also a significant show of intent in the present.
Andre Villas-Boas and his coaching staff will have been examining just how they might get the better of Sir Alex Ferguson's table-toppers. Having defeated them once already, have they got a ready-made winning formula to call back on?
Yes and no.
Man United struggled at times to deal with Tottenham's speed in September. Notably, for their second goal, they counter-attacked swiftly and directly at the heart of the United defense.
Having collected the ball in his own half, Mousa Dembele suddenly upped the tempo, catching the Red Devils flatfooted to the extent they were already yards behind Gareth Bale when he received the ball. Even Jermain Defoe could be seen charging across the field and bringing Jonny Evans along with him to make space for his teammate to gleefully dash into and shoot.
Spurs undoubtedly look their most dangerous in such moments, and since that day, they have often been at their best when taking the game directly to an opponent's defense.
Yet even in the course of that match, Ferguson found a way to nullify that threat, pushing his team forward to such a degree they barely allowed the away side out of their own half after their third goal. Considering Man United have improved since then, they might be able to use this strategy for a full 90 minutes this weekend.
For Tottenham to stand a chance of winning, Villas-Boas needs to find a way to encourage his team forward without leaving them unnecessarily exposed to the substantial United attacking threat.
Back in September Tottenham managed to eventually hold United off through sheer defensive effort. But there was an element of luck to their victory too, as well as examples of lapses in concentration and disorganization in the goals they conceded that had already cost them points and would do so again.
Encouragingly for Villas-Boas, his team are better defensively than they were then. Spurs are not so prone to ball-watching, which will stand them in good stead if they hope to keep out a Man United forward line capable of taking advantage of any disregard for their presence and movement.
Still, the Spurs defense will need their teammates further forward to ensure they are given some time to breathe. It will be a hard task to once again withstand sustained pressure of the sort United applied last time the teams met.
Had Emmanuel Adebayor not already left to represent Togo at the African Cup of Nations, it would have been interesting to see whether Villas-Boas would have played two strikers up front against United.
The last time they did so against one of the Premier League's top teams was against Arsenal in November. For almost 20 minutes it worked well, as Spurs showed signs of overwhelming the Gunners before Adebayor's dismissal saw the tide turn in horrific fashion.
Instead Tottenham will almost certainly revert to the 4-2-3-1 formation they generally deployed up until early December, with Clint Dempsey the likely replacement for Adebayor. The American, along with wingers Gareth Bale and Aaron Lennon, will be tasked with getting forward in support of Jermain Defoe. It is imperative they do so to avoid the lone striker from getting isolated.
Even if they are unable to pressure United to the extent they have other teams, with the pace and instincts for getting into goalscoring positions those four possess, they are capable of hurting the Red Devils as they did before.
Spurs might not deliver well enough on set pieces to expose United's flaws, but in open play, their ability to cross and put Defoe and Dempsey in good positions could prove as dangerous as the likes of Robin van Persie will be for United.
Timing will be important here for Spurs, as they must maintain possession (and therefore keep United off the ball) without forsaking their ability to strike quickly. The midfield pairing of (presumably) Dembele and Scott Parker will be vital in this regard.
As two players who will see a lot of the ball, they carry a large part of the responsibility in judging when to instigate a potential attack and when to keep things ticking over. Since they are also tasked with breaking up United's advances, they know their decisions here will influence how often they are needed to stop them.
The injured Sandro will be missed defensively, but Parker is an adequate replacement here and is arguably better at driving his team forward.
A lot has to go right for Tottenham Hotspur to beat a team as good as Manchester United. Their struggles against them over so many years show that fact.
But it is refreshing for both Spurs supporters and neutrals hoping for a more competitive Premier League that Villas-Boas' team have shown themselves capable of doing so.