Clearly, Sir Alex Ferguson does not think it feasible that on the last day of the season Manchester United could drop two points against Wigan Athletic, as Liverpool, Arsenal and Chelsea have done in the past four months. Plainly, he believes it impossible that Saturday’s meeting with West Ham United should end in anything other than victory, unlike the game in December when Manchester United lost at Upton Park, as did Liverpool in January.

And he is probably right. On paper, there is no way those matches fail to bring six points for United and his decision to rest important players – including Cristiano Ronaldo, Carlos Tévez, Patrice Evra and Paul Scholes – for a match after which Chelsea pulled level on points at the top of the table for the first time since José Mourinho was manager, will in time be vindicated by United’s superior goal difference.

Ferguson is known to be a gambler, though, and this is perhaps his greatest yet. What happens if United have what football folk know as one of those days? One of those days that they had on May 14, 1995, when a goal by Michael Hughes and a heroic performance from Ludek Miklosko, the West Ham goalkeeper, denied Ferguson’s team victory on the final afternoon of the season and sent the title to Blackburn Rovers.

What if West Ham have one of those days, as on April 7, 2007, when they should have gone down by a double-figure scoreline at the Emirates Stadium, yet instead defeated Arsenal with a single goal from Bobby Zamora and 90 minutes of perfection from Robert Green, the goalkeeper. It happens. We have all seen it.

The best team do not always win, but what Ferguson has left to chance is that this season, that statement could be true of the title, as well as individual matches. The United manager expressed his anger at Alan Wiley, the referee, after the match as his foolish players sought to score meaningless points by confronting stewards and groundstaff, but he was stewing in his own juice.

“Never give a sucker an even break or smarten up a chump,” W. C. Fields said. That is what United did on Saturday. Chelsea were the suckers who conceded a 94th-minute goal to Emile Heskey, of Wigan, this month and looked to have surrendered their title aspirations, Avram Grant the chump who sent out a below-strength team for that match, which had to be won, and was left scratching his head on the sidelines as his plan fell apart. Now he is back in the game.

“Horse sense is a thing the horse has that stops it betting on people,” Fields claimed, and Ferguson is having a big bet on people right now. He needs people to behave with absolute consistency in the next two weeks, with no unexpected changes in mood or performance and unaffected by twists of fate. He needs his people not to be unnerved by the pressure of the closest title race since the 1998-99 season, when United led Arsenal by a point on the last day and went a goal down at home to Tottenham Hotspur after 24 minutes before rallying.

He needs the people of West Ham and Wigan not to be inspired at the thought of having the only impact that players at small clubs can have on the title race: by screwing it up for someone else. Ferguson needs a whole disparate bunch of people to behave exactly as expected for the next two weeks. That is some bet.

Forget the conspiracy theories: that Alan Curbishley, the West Ham manager, is a friend of Ferguson and will be looking to repay a courtesy from last season, when United, with the title secured and one eye on the FA Cup Final, fielded an understrength team in the final league match, which West Ham won to stay up. Curbishley’s club have twice denied United the title and the fans will expect Curbishley to try to maintain tradition. Hardly winning many popularity contests in East London right now, a weakened team or half-hearted display may be the final straw for the manager. West Ham cannot afford to roll over at Old Trafford, no matter how inconsequential their season.

Wigan, neither. Steve Bruce, the manager, may have been Ferguson’s first title-winning captain at United, but he also has a duty to his career. He has designs on managing the biggest clubs and how can he prove his credentials at lowly Wigan if not with results that put a marker down, such as the draw away to Chelsea on April 14 or staunch resistance to United on the final day of the season?

“The first year I was here as a child, 1972, Leeds United needed one point against Wolverhampton Wanderers away,” Grant, the Chelsea first-team coach, said. “Leeds lost to Wolves, so Derby won the title. I believe in that tradition – the English way. So it could happen that United drop points against Wigan and West Ham. They have dropped points against West Ham in the past few years and Wigan is not an easy place to win.”

The toughest match to be faced by either United or Chelsea in the next two weeks is Chelsea’s visit to Newcastle United a week today, but for now the burden is on Ferguson. When Ricardo Carvalho’s feeble pass handed an equaliser to Wayne Rooney in the 58th minute, it looked as if the marathon sprint might become a gentle jog across the finish line, but Michael Carrick’s handball and Michael Ballack’s perfectly taken penalty – to go with his fine first-half header – stopped that happening.

“I have been in United’s position and lost the league twice at Bayer Leverkusen,” Ballack said. “We were beaten like that by Bayern Munich in 2000 and Borussia Dortmund in 2002. I know what can happen and how. In 2002, we went into the last game two points in front and lost, Dortmund won and that was the title decided. It can change like that, right until the last minute.

“All the pressure is on United. Last week it looked as though they were the champions, that nobody could catch them. Now there is no gap.”

If everyone wins their matches, United will take the league on goal difference. Yet if there is a slip, a miscalculation, one tiny variation or contradiction to the norm, United are vulnerable.

Everybody knew that Ferguson liked a punt; what no one realised was how much he was prepared to gamble. He must be one of those people who can never see a favourite being beaten; the poorhouses are full of them. How they rated

Chelsea (4-3-3): P Cech 7 – P Ferreira 6 R Carvalho 7 J Terry 7 A Cole 8 – M Essien 8 J O Mikel Y 7 M Ballack Y 8 J Cole 7 – D Drogba Y 7 S Kalou 7 Substitutes: N Anelka 5 (for Ferreira, 66min), A Shevchenko (for Kalou, 80), C Makelele (for J Cole, 87). Not used: C Cudicini, J Belletti. Next: Newcastle (a).

Manchester United (4-2-3-1): E van der Sar Y 7 – W Brown Y 6 R Ferdinand Y 7 N Vidic M Silvestre 6 – D Fletcher 6 M Carrick 6 Nani 6 Anderson 6 R Giggs 5 – W Rooney 7 Substitutes: O Hargreaves 5 (for Vidic, 13min), C Ronaldo 6 (for Rooney, 63), J O’Shea 5 (for Anderson, 65). Not used: T Kuszczak, C Tévez. Next: West Ham (h).