English FA Premiership/ Manchester Utd 1 Chelsea 1:An afternoon that left the top of the table undisturbed still carried portents of transformations to come. While Manchester United could have opened up a 2-0 lead, the life was gradually drained from them as the indomitable visitors showed why Martin O'Neill calls Chelsea the most powerful team in Europe.

Physical strength allied to improved co-ordination after the interval threw a bellowing crowd into an introspective mood at the close.

Even if they are far from being the most cultivated of teams, this sort of vigour threatens to take Chelsea clear of all rivals in the long run.

United, despite letting a lead slip, cannot even think of too many faults that they can fix in the near future. Alex Ferguson's team must only lament the openings that tended to slip away from them.

Louis Saha, who had already put United in front, was unable to capitalise after Wayne Rooney had beaten Didier Drogba and pitched a cross into the centre after 49 minutes. And the ball would not quite fall to him in the 58th minute after a Gabriel Heinze cross had been chested down by Cristiano Ronaldo.

No matter where they stand at the end of the campaign, United will lead Chelsea in popularity charts. They delivered the entertainment, while Jose Mourinho's side made do with inspiring a sense of foreboding among their enemies.

For a club of such intimidating means, the footballers, all the same, were scrappy.

Mourinho even had to abandon his preferred strategy for this campaign. The trio of Michael Essien, Michael Ballack and Frank Lampard that he stations in front of Claude Makelele were too narrow, too liable to be caught up in the snarl and shove of the contest.

Arjen Robben came on and hardly delighted his boss. Mourinho even walked to the edge of the technical area to bawl and gesticulate when the Dutchman knocked a pass out of play, but the winger opened out Chelsea's approach.

Essien did even more in that regard once Geremi was removed and the Ghanaian went to right-back.

To be more accurate, he went virtually everywhere. Essien was dynamic all the way down that flank, with such energy and skill to spare that he bolstered the heart of the midfield from time to time. This figure epitomised that mixture of ability and resolve that has set Chelsea apart.

Essien forced a corner in the 69th minute and when Lampard struck it deep Ricardo Carvalho leapt above Heinze to connect. The effort might have been blocked by the hands of Edwin van der Sar had not a slight touch from the head of Saha sent it against the underside of the crossbar and into the net. Carvalho is likely to be credited with the goal since his attempt was on target.

Saha will take no solace from that. That mishap cannot be overcome with a shrug by a man who had squandered a prime opportunity and missed a penalty during the 1-0 defeat by Celtic five days earlier.

It will exasperate him as well that he could have been the player who separated the teams instead of the cursed individual who left them tied.

After 29 minutes he had been picked out by a Wayne Rooney pass from the centre-circle. Saha had the space to move and the generally interventionist Carvalho backed off for once. The centre-half calculated that his opponent could not score from 20 yards, only to learn that he had underestimated him. With his left foot, Saha curled a low finish that beat Carlo Cudicini at the near post.

That was the hallmark moment of a period when everything ran true for United. The defence stood firm, Michael Carrick had the administration of midfield matters under his command, others were enterprising and Rooney's drifts towards the left did not cancel out his talent as they sometimes can. For all that, Ferguson's side failed to polish off Chelsea.

Severe as it is to blame a person who froths with so much talent, Ronaldo can embody unfulfilled potential. There are too many afternoons when he has the air of a match-winner throughout, yet turns out to have made no great difference at all.

Allowances, admittedly, do have to be made for the taxing nature of the mission he was taking on at Old Trafford.

Ashley Cole, a nimble and gritty left-back, is a match for his wiles and pace, as was shown memorably in the Euro 2004 quarter-final between England and Portugal. Yesterday's often indifferent fixture bore no resemblance to that clash, but the duel between the men was absorbing. It was distasteful that the exchanges culminated in a bad tackle for which Cole was booked and the departure of Ronaldo with a hamstring problem. But he is expected to be fit for Wednesday's home game with Everton.

That incident will exasperate United, yet the various disappointments should not detract from the fact they are making progress. Nemanja Vidic has reinforced the defence and Drogba, mostly contained yesterday, grew peevish.

The centre-forward, who seemed to peek at the Serbian centre-back before swinging an arm into his head after 35 minutes, could well have been dismissed instead of cautioned.

Chelsea seldom perform with overwhelming style and Mourinho should be queasy after spending £30 million on Andriy Shevchenko, a striker who may have lost the pace on which he depends. The midweek fixture at Bolton could be nerve-racking as well. Yet Chelsea do have the resolve to realise most ambitions, as they did in denying United yesterday.

• Guardian Service