Coventry City gave the champions a timely reminder yesterday that despite their frightening lead at the top of the table, complacency comes before a fall. On St Stephen's Day everyone thought Manchester United were cantering to their third championship running and a fourth in five years.

At Highfield Road it appeared the team did, too, and they paid for that nonchalance when as sloppy a performance as they have produced all season reaped the reward it deserved in embarrassing defeat.

Coventry's five defeats in their previous six games had seen them slip into familiar relegation territory, contrasting starkly with United's run of six straight Premiership victories. A record of no win and 14 defeats in Coventry's previous 17 league meetings with United cast further doubt on an upset.

But the champions began as if they were playing an exhibition match, full of flicks and what Alex Ferguson castigated as "too much of the pretty stuff". They went behind on 13 minutes and though they pulled back to lead 2-1 three minutes after the break, they failed to capitalise on the momentum. They gave the ball away carelessly, sat back in midfield, defended too deep and allowed a persistent Coventry to come at them.

The home side took full advantage by scoring two goals in the last four minutes, the winner a brilliant solo effort from Darren Huckerby, who unnerved United with his pace and directness all afternoon. It sealed a victory for Gordon Strachan's side that was as important for the lift it gives to morale as the team's position in the table.

"When I was driving into the game today," said Strachan, "I was confident that I would get the commitment and right attitude from the players."

Ferguson admitted afterwards: "We were silly and on the whole we got what we deserved. Players can get careless at times and overconfident. Coventry, in all honesty, never really looked like scoring and yet they've ended up with three goals."

The writing was on the wall as early as the 13th minute when Coventry took the lead. Noel Whelan's incisive ball out wide fed Marcus Hall on the left and, though he was tackled near the byline by Henning Berg, for a split second the ball sat on the wet turf, motionless and untouched. Huckerby was the quickest witted, poking out a foot to direct the ball into the area where Dion Dublin set up Whelan, the original instigator, who scored from eight yards.

Four minutes later Coventry should have gone 2-0 ahead when Kevin Pilkington, deputising again in goal in the absence of the injured Peter Schmeichel, came charging out his area, missed the ball but Huckerby hit the ide-netting with team-mates waiting in the middle.

Teddy Sheringham forced a fine reflex save from Coventry's new goalkeeper Magnus Hedman, and the home fans launched into a cheeky chorus of "Can we play you every week?".

Once again cockiness was soon punished as United equalised. The goal exposed the thin line that separates success from failure as Coventry launched a wonderful attack full of breathtaking one-twos, pace and movement. Unfortunately, the new signing George Boateng could not continue such excellence and his final pass went straight to Gary Pallister.

One of the many things that United do well is counterattack. Paul Scholes found Ryan Giggs, whose burst forward down the centre ended with a smart pass out to the right to Ole Gunnar Solskjaer. A sublime shoulderdrop shimmy took him past Roland Nilsson and, from the acutest of angles, the Norwegian found the net.

By now United had tightened up their act and three minutes into the second half they went ahead. Whelan was caught in possession by David Beckham, Scholes picked up the loose ball and his quick cross to the far post set up the unmarked Sheringham for a header and his 10th goal of the season.

Instead of going for the kill, United sat back, kept losing the ball and generally invited Coventry to equalise. Paul Telfer and Huckerby had already shot inches over when on 86 minutes Huckerby once again ran at Berg. The full-back had been committing fouls on the striker at regular intervals, but this time he was punished as Huckerby went down in the penalty area. Dublin stepped up to score from the spot against his former club.

Two minutes later came the goal of the game when Huckerby was allowed to pick up the ball and turn some 30 yards out. Again he dashed at United's defence, with a little luck sailed past four defenders and slotted the ball beyond Pilkington.

Blackburn failed to capitalise fully on United's unsuspected slip and even if Chelsea win at Southampton tonight, their lead will still be four points. Even so, this result was an unfitting end to a great year for United.

If 1998 turns out to be even greater, it may be due, in some small part, to the lesson learned from this unhappy performance.