David Gill has been appointed as chief executive of Manchester United "with immediate effect" following the resignation of Peter Kenyon who is expected to take a similar role at Chelsea.
The move follows hard on the heels of reports that Kenyon - said to be in London on business today - was set to defect to Stamford Bridge.
United released a statement which said: "The board of Manchester United plc is delighted to announce the appointment of David Gill as its new chief executive with immediate effect, to replace Peter Kenyon who has resigned today.
"Mr Kenyon will now go on `garden leave' in accordance with the terms of his contract."
Manchester United plc chairman Sir Roy Gardner added: "We would like to thank Peter for his significant contribution to the success of Manchester United on and off the pitch in the last six years.
"David, as managing director, has also played a major role in that success, and we are delighted that his appointment will bring both experience and continuity to this position."
Kenyon's imminent boardroom transfer to Chelsea has been read as a signal that Roman Abramovich is intent on challenging United's supremacy on the commercial front as well as on the pitch.
The Russian billionaire took a matter of weeks to establish the west London club as prime movers in the transfer market with a spending spree unprecedented in the history of the game.
Well over £100 million of Abramovich's oil fortune has been pumped into Claudio Ranieri's side but the decision to take the same aggressive approach with a boardroom recruit points to the Russian's desire to make his revolution pay for itself.
Kenyon has been given a good deal of credit for making United a commercial success as impervious to financial downturns as any publicly listed company can be.
With most clubs across world football forced to tighten their belts significantly, football affairs at Old Trafford have gone on much as they have for the past decade.
And former Chelsea chief executive Colin Hutchinson believes Kenyon will be asked to give the Blues the same stability.
He told Sky Sports News: "As part of the new Chelsea they have brought the guy in to presumably try to surpass United.
"He is a very good businessman. I think it is fair to say that what he has done commercially has made them streets ahead in England as far as resources are concerned."
Kenyon, who became a United fan when his father took him to seem them beat Benfica in the 1968 European Cup final at Wembley, arrived at Old Trafford from Umbro International in 1997.