This was a romantic tale speared by a twisted knife. Joe Cole, the name on everybody's lips, had done all that he could to steal West Ham hearts all over again. He looked like being the game's catalyst, as he helped his team to recover from a goal deficit with two creative deliveries that James Collins finished off gleefully. He took a blow to the face that made him bleed, and had to change his shirt to one unembellished by his identity, as if anyone in these parts could ever forget. It was too perfect.

But just as West Ham and Joe Cole were reaquainting their relationship in the sweetest way possible, Robin van Persie arrived to throw a metaphorical bucket of icy water all over the cosy claret and blue love-in. A stoppage-time equaliser by the substitute spared Manchester United embarrassment and continued the trail of electrifying comebacks.

There is nothing surprising about a Van Persie goal these days. This was his 22nd from 28 games since joining United. But that hardly lessens the dramatic impression he is so eminently capable of leaving on a game. In the second that he burst away from James Tompkins, bearing down on Jussi Jaaskelainen's goal like a lion homing in on its prey, there could not have been a soul in the stadium who didn't know what was about to happen.

That is what you get with a striker as extraordinarily productive as he is. United's band of fans rose to acclaim salvation even before Van Persie was in position to pull the trigger. The West Ham majority feared the inevitable. "The pass from Ryan Giggs, the first touch of the ball from Robin, and his finish, was absolutely world class," Sir Alex Ferguson said.

United had few complaints about their start and their finish but the spell in-between was less encouraging. Although Ferguson tinkered with more than half of this team compared with the starting XI who swatted aside Wigan it was still a selection strong enough on experience and quality.

In the 23rd minute, Javier Hernández broke down the right and whipped in a cross that careered all the way to Tom Cleverley, who arrived from his station on the left to beat Jaaskelainen with panache. He exhibited sweet technique to curve his shot, with perfect placement, inside the far post. Up in an executive box, the junior members of the Beckham family celebrated enthusiastically.

The lead proved to be short lived as West Ham came bouncing back four minutes later. Joe Cole was the provider, receiving the ball from Ricardo Vaz Tê, turning, looking up and lofting a cross that was gobbled up by Collins.

The fairytale element to the occasion was in full swing. The 31-year-old, hair a little thinner on top than when he was last revered here, looked understandably low on match fitness. But his appetite was cranked up. He craved the ball. He looked so eager to feel boot on ball, to spot a pass.

There were other reasons for Sam Allardyce to cheer. He was delighted with the performance of the teenage defender Dan Potts, who was recalled from a loan period at Colchester, and pleased for Alou Diarra, Vaz Tê and Jack Collison to get some high-intensity football after lengthy injuries.

Just before the hour mark, Joe Cole combined again with Collins to fantastic effect, sending in another searching pass that the defender glanced in superbly.

United had been careless from promising positions, with Danny Welbeck enduring a game to forget. It was time to get serious. Ferguson sent on Van Persie, Antonio Valencia and Giggs.

The home crowd saw four minutes of additional time go up on the clock and gave out a collective groan. If they sensed that something was coming, they were right. In an instant, Van Persie was freed, accelerating down the right channel to finish with devastating precision. "You never rule out fighting back with our team but certainly at 2-1 down with a couple of minutes to go you hope you get a break," Ferguson said.

"The manner of the goal was absolutely world class, absolutely fantastic. It is a new challenge here for Robin van Persie. He is a well-established international, he is a mature age and he has brought that maturity to the front line. His performance was tremendous."

Naturally, Allardyce's sentiments were rather different. "I am more than disappointed," he said. "The finish was just unbelievable but we almost feel like we lost in that dressing room. We have got a difficult January now."

Fitting in the replay, in addition to the Arsenal match that was postponed from Boxing Day, brings a busy schedule. After a topsy turvy and compelling game, Manchester United and West Ham will meet again at Old Trafford on 15 January. The Londoners could do without coming across Van Persie again in a hurry.