Wilkins had been preparing Fulham - who are owned by Mohammed Al Fayed - for tomorrow's first leg of the play-off semi-final at home to Grimsby. A terse statement from Craven Cottage then announced the termination of his contract "with immediate effect".
It added that Keegan, nominally Fulham's chief operating officer, would take responsibility for the team in their forthcoming games. No reasons were given for one former England captain replacing another, and the statement ended: "No further comment will be made by either party."
But the timing of the change - 48 hours before Fulham's biggest match since they narrowly missed promotion to the top division in 1981 - raised the possibility of a personality clash. It soon transpired that the duo had disagreed over what Keegan termed "the playing side", leading to his asserting seniority and asking Wilkins to leave.
In an interview with ClubCall, Keegan said: "When Ray took the job he knew that ultimately I had to make those final decisions on football, and was responsible for it to Mr Fayed. We had a sensible meeting between two guys who've known each other a very long time and also were good friends, and still are.
"We've had to part company because we've had a difference of opinion. I don't want to go into the oohs and aahs of that [but] Ray's a very nice guy who listened to what I'd got to say and had his opinion.
"At the end we realised we'd come to a point where one of us had to go. I could step in and take over until the end of the season. It's not like I'm coming in cold - I know all the players and signed them along with Ray, and I've been to every match bar one, when I was watching a player."
Keegan said he had received a "fantastic response" in training yesterday. Wilkins, meanwhile, restricted himself to a brief comment: "It's very sad but I can't say too much more at the moment. It's a delicate matter and all I want to do now is wish the players the best of luck."
Keegan's decision to take a more hands-on approach follows three successive defeats which saw Fulham scrape into the play-offs in sixth place. The team stood 11th when they arrived last September after Al Fayed dismissed Micky Adams.
Fulham spent pounds 7m on players in the ensuing eight months, so it is likely that their owner anticipated a smoother start to his five-year plan to make Chelsea's under-achieving neighbours "the Manchester United of the south".
Wilkins' exit, two years after he lost his job at nearby Queen's Park Ranegers, revived speculation that Ruud Gullit may be lined up for a return to west London. However, a spokesman for his management company said: "He knows nothing in the world about the English Second Division. There's just no chance of it happening."