Sir Alex Ferguson has lost Premier League titles on the season's closing day before – or in those fraught last few weeks in May that he once said can have a direct effect on a manager's digestive system – but he has never lost a title in the circumstances that he is threatening to lose this one.
This year's squeaky-bum time is not so much a neck-and-neck race – although that is what it has become with Chelsea – as the story of how Carlo Ancelotti's team have reeled Manchester United in after an improbable change in fortunes. United are in danger of throwing away the lead they held over Chelsea, one considerably larger than the lead they closed on Kevin Keegan's Newcastle United in the 1995-96 season.
At half-time at Stamford Bridge on 1 March, United were 1-0 up against Chelsea and looking at opening up an 18-point gap on the defending champions. They lost the game in the second half, cutting their lead to 12 points over Ancelotti's team, who were then fourth in the table. Should United lose to Chelsea at Old Trafford on Sunday, Chelsea will have closed the gap to zero and lead the Premier League on goal difference.
It was while he was in the process of tossing away a 12-point lead to United in 1996 that Keegan donned a large pair of studio headphones and subsequently lost his rag in a live interview. That is the size of the potential choke we are talking about here – if United throw this one away, all bets are off. Even Keegan did not blow it in such grand style.
It is typical of United's season of contrasting fortunes – are they Ferguson's worst team since 1993 or his greatest in the making? – that this United side could blow a crucial game against a club who have already taken a lit match to their own season.
With the pressure off and nothing of note to play for, Arsenal put on a performance worthy of a team with title-winning aspiration. They won the game with a goal from Aaron Ramsey, the first since he broke his tibia and fibula against Stoke City in February last year, and for a large part of the game Arsenal were a more attacking, aggressive force than their opposition.
For their long-suffering supporters it was, at last, a result in which they could glory. But what are the consequences? Could it be that this victory will only make Arsène Wenger more entrenched in his view that no major changes are needed this summer? For every silver lining at Arsenal, there is that inevitable cloud. One win over United does not change the fact that Wenger needs two new central defenders, as well as a central midfielder and a striker at the very least.
Nonetheless, they were excellent yesterday, particularly in the central midfield pairing of Ramsey and Jack Wilshere, who played together in the absence of Cesc Fabregas, withdrawn with a thigh injury picked up in training.
If Fabregas does leave for Barcelona this summer then the future looks tolerable, although that does not mean Arsenal will not need at least one more midfielder in the summer. Yesterday they started strongly, with an in-form Robin van Persie a crucial factor, and even when they did not take advantage of their bright start they resisted the trap of sliding away in the second half.
The game featured two penalty appeals, both of which should have been given by the referee Chris Foy and his assistant Andy Garratt. In the first half the linesman failed to spot Nemanja Vidic reach out a hand and touch a cross from Theo Walcott on the right wing, aimed for Van Persie. With three minutes left Gaël Clichy brought his studs down on Michael Owen's calf in the same area and got away with it.
Everywhere United excelled against Schalke last Tuesday, they failed to repeat yesterday. The likes of Javier Hernandez, Park Ji-sung and Michael Carrick all failed to spark in the same way. The difficult question for Ferguson now is whether he rests players for Wednesday's return leg against Schalke in anticipation of Chelsea's visit on Sunday.
It is a Hobson's choice and at this stage of the season a manager fighting on more than one front can do little more than pick his best team – give or take the occasional change – and hope the adrenaline gets his players through. United's misfortune is that they are incapable of building any momentum to extinguish the hopes of their title challengers once and for all.
When John Terry spoke, in the aftermath of Chelsea's win over Tottenham on Saturday, about the danger Arsenal posed to United at home it sounded – on recent evidence, at least – like wishful thinking. But they got the basics right yesterday. In goal Wojciech Szczesny was solid, pulling off a fine save from Nani on 76 minutes. The full-backs Bacary Sagna and Clichy were dominant on the wings.
The only goal came a matter of minutes after Ferguson had substituted his midfielder Anderson for Antonio Valencia on 55 minutes, in what looked like an attempt to force the issue with Arsenal. The move for the goal began with Ramsey in the hole Anderson had vacated. Van Persie ran at United down their left and when Ramsey popped up in the box, the return pass found him in space, allowing him to hit the corner of the goal.
There was the suggestion of a nasty off-the-ball tangle between Van Persie and Rio Ferdinand on 84 minutes, in which it looked like Van Persie had been the aggressor, although no replay was forthcoming. Even Owen admitted on Twitter that his own penalty call was just as valid as Arsenal's in the first half, although that was not a sentiment shared by his manager.
United are still in the box seat in this title race and a win over Chelsea on Sunday will put them six points clear with two games to play. As no pattern has ever emerged in this title race, it would be unwise to assume that yesterday's defeat was the start of a damaging slump for United. But they do not want to be the team that blew a 15-point lead over Chelsea – and that itself can affect the most single-minded of teams.
Substitutes: Arsenal Arshavin 6 (Nasri, h/t), Squillaci 6 (Djourou, 69), Eboue (Walcott, 78). Manchester United Valencia 6 (Anderson, 55), Berbatov (Hernandez, 73), Owen (Carrick, 84). Booked: Arsenal Ramsey, Song. Manchester United Rooney, Park, Fabio.
Man of the match Wilshere.
Referee C Foy (Lancashire)
Race for the title
Top three's remaining fixtures:
* Manchester United
Chelsea (h) Sunday
Blackburn Rovers (a) Sat 14 May
Blackpool (h) Sun 22 May
Manchester United (a) Sunday
Newcastle (h) Sun 15 May
Everton (a) Sun 22 May
Stoke City (a) Sunday
Aston Villa (h) Sun 15 May
Fulham (a) Sun 22 May