Demonstrating that they are a team for all seasons, United retrieved a two-goal deficit on a pitch which often resembled a lake, exactly as they had done in searing heat at Leicester 48 hours earlier. But Middlesbrough, despite losing Fabrizio Ravanelli to a torn hamstring that makes him doubtful for the FA Cup final, refused to relinquish a vital point towards their struggle against relegation.
United will be crowned champions for the fourth time in five seasons if both Newcastle and Liverpool lose in London tonight. Even if both their rivals keep up the pursuit, they have two further opportunities to secure the victory that would enable them to take the trophy in front of their own fans for the first time since 1965: against Newcastle on Thursday and West Ham on Sunday.
Middlesbrough must also cram in two fixtures, at Blackburn and Leeds, and might need to win both to survive. Without the 31-goal Italian, it will be a tall order, yet to judge by this performance they may have just enough fire to overcome the inevitable fatigue.
If anything, United showed greater signs of strain. For much of the first half, a Middlesbrough side inspired by the genius of Juninho exposed an uncertainty at the heart of Alex Ferguson's defence which should encourage Messrs Hartson and Kitson, let alone Shearer and Ferdinand. "The worst we've defended in six years," the United manager complained.
A year to the day after regaining the championship by overcoming Middlesbrough at the Riverside Stadium, United found Bryan Robson's team more resilient on his return to the theatre of dreams. It was more like a theatre of streams, with so much rain falling during the match, but Boro initially made light of both the conditions and their parlous position to drive forward with a purpose that belied their draining schedule.
Ravanelli had already shaken Peter Schmeichel's left-hand upright before they took the lead with a sumptuous goal after 15 minutes. In a patient build-up of 18 passes, which took them from the left-back position to the inside-right channel and then left again, Juninho was involved on five occasions. The Brazilian's last touch, after Craig Hignett spotted him overlapping, was to angle the ball beyond the goalkeeper for his 14th goal of the season.
A flurry of four goals in eight minutes took both teams through the gamut of emotions. Middlesbrough were probably distracted by the melodrama of Ravanelli's injury when their goal fell in the 34th minute.
Andy Cole, spinning sharply near the penalty spot, saw his shot blocked by Gianluca Festa. But the ball broke to Roy Keane, who drilled in only his second goal of the campaign. Only then did Ravanelli hobble off clutching his thigh.
Yet within five minutes, Boro were two goals to the good, having again shown what a fine side they can be going forward. Juninho launched the move which restored their advantage, contemptuously skipping past Gary Neville before seeking out Chris Freestone. With his first touch of the game, Ravanelli's replacement played in Emerson, who bludgeoned a first- time shot home off the underside of the bar.
United were still trying to take in their plight when it deepened. Another sweet exchange of passes, again involving Freestone, saw Robbie Mustoe surging into the box on the right flank. Nominally his team's token defensive midfielder, Mustoe delivered a textbook cross which Hignett headed home after stealing in front of Gary Neville.
Despite conceding three goals for the second Premiership home game in succession, United's reaction was typically positive. Three minutes before half-time, with white-shirted defenders massing in front of Ben Roberts, Cole and the strangely ineffectual Eric Cantona worked the ball wide for Gary Neville to bullet a diagonal drive past the keeper for his first senior goal.
For most of the second half, Middlesbrough were pushed back. Juninho began to show that he was mortal after all, performing in fits and starts where previously he had been poetry in motion. However, United also found the going heavy, both literally and mentally, and did not restore parity until the 67th minute.
Nigel Pearson and his fellow defenders had dealt admirably, often bravely, with a succession of crosses by David Beckham which dipped out of the slate grey sky like shells. But when Gary Neville ploughed forward to cross, Ole Gunnar Solskjaer materialised unmarked to head his 18th goal of a remarkable first season.
The drama would have been complete had the referee awarded a penalty after Denis Irwin fell under a challenge from Phil Stamp with five minutes remaining. The only doubt appeared to centre on whether it was a foul or obstruction, which would have produced a free-kick. Mr Gallagher, lenient to the last, had detected neither offence.
Middlesbrough thus left Old Trafford having played a full part in a six- goal spectacular, less than a month after sharing an identical scoreline with Chesterfield at the same venue. On that occasion they went on to succeed at the second attempt. Neutrals may now be hoping for a similar outcome, if only to guarantee the continued presence of Juninho in the English game.
Manchester United (4-3-1-2): Schmeichel; G Neville, May, Pallister, Irwin; Beckham, Johnsen (Scholes, 73), Keane; Cantona; Solskjaer, Cole. Substitutes not used: P Neville, McClair, Poborsky, Van der Gouw (gk)
Middlesbrough (4-4-1-1): Roberts; Fleming, Pearson, Festa, Blackmore; Stamp, Mustoe, Emerson (Kinder, 87), Hignett (Vickers, 75); Juninho; Ravanelli (Freestone, 36). Substitutes not used: Cox, Whyte.
Referee: D Gallagher (Banbury).
FA Carling Premiership
P W D L F A Pts
Man Utd 36 20 11 5 74 44 71
Liverpool 36 19 10 7 60 34 67
Arsenal 37 18 11 8 59 31 65
Newcastle 35 18 9 8 68 40 63
Aston Villa 37 16 10 11 46 34 58
Chelsea 37 15 11 11 56 54 56
Sheff Wed 36 14 14 8 49 49 56
Wimbledon 36 13 11 12 46 45 50
Tottenham 37 13 7 17 43 49 46
Derby 37 11 13 13 44 55 46
Leeds 37 11 12 14 27 37 45
Everton 37 10 12 15 43 55 42
Blackburn 36 9 14 13 40 39 41
Southampton 37 10 11 16 50 55 41
West Ham 36 10 11 15 39 46 41
Leicester 36 10 11 15 41 52 41
Sunderland 37 10 10 17 35 52 40
Coventry 37 8 14 15 36 53 38
Middlesbro* 36 10 10 16 50 59 37
N Forest (R) 37 6 16 15 31 54 34
*Middlesbrough deducted three points
Wimbledon v Liverpool
West Ham United v Newcastle United
Leicester v Sheffield Wednesday
Blackburn Rovers v Middlesbrough
Manchester United v Newcastle United
Aston Villa v Southampton
Blackburn Rovers v Leicester City
Derby County v Arsenal
Everton v Chelsea
Leeds United v Middlesbrough
Manchester United v West Ham United
Newcastle United v Nottingham Forest
Sheffield Wednesday v Liverpool
Tottenham Hotspur v Coventry
Wimbledon v Sunderland