Chelsea’s dazzling second-half comeback against Manchester United in an FA Cup clash at Old Trafford that looked to have been lost impressed even the dour Alex Ferguson.

“We’re lucky to be in the cup,” he conceded after the 2-2 draw.

“We just ran out of legs, and Chelsea were far the better team in the second half.”

What made the turnaround more remarkable was that the Blues appeared dead and buried after 11 minutes, with Javier Hernandez and Wayne Rooney scoring in rapid succession.

To a chorus of “You don’t know what you’re doing”, Rafa Benitez shuffled the pack after the interval, taking off Frank Lampard and Victor Moses and replacing them with Jon Obi Mikel and Eden Hazard.

Swapping Moses for Hazard seemed obvious, but it was the introduction of Mikel that provided the platform for Chelsea to regroup and get a grip on this enthralling game.

He freed up Oscar, Ramires and Juan Mata to create more threatening attacks and, suddenly, United were on the back foot.

Hazard and Ramires levelled, and at the end it was the Reds clinging on.

If Chelsea can replicate that attacking storm against West Ham at the Bridge on Sunday, the manoeuvring for Champions League places will get even more spicy.

Fergie’s assertion that United faded because they had endured a tiring game against Real Madrid on the Tuesday was simply pathetic.

The Blues only returned from an expedition to Romania on the Friday, so had far more reason to feel a bit cream-crackered.

In the course of this crazy season, Chelsea have already played eight games more than United. But the true freshness test comes this weekend.

Since the start of February, the Hammers have played four times, with a trip to Stoke their most arduous in terms of journey time. In that same period, Chelsea have had 10 bruising games, travelling to Middlesbrough, Newcastle, Manchester (twice), Prague and Bucharest in the process.