Mohamed Al Fayed, the Fulham chairman, lambasted Mark Hughes in an open letter on Monday after the former manager criticised the club as lacking ambition.
In the letter posted on Fulham's website, Al Fayed disputed a claim by Hughes in a weekend newspaper interview that he quit in June because the west London club were going nowhere.
Hughes told a British tabloid that the club would not provide him with a big enough budget to fulfil his personal aim of regularly finishing in the top half of the table.
"He insults the club, saying it lacks ambition, and the players who delivered an eighth position finish last season and a place in the Europa League," Al Fayed wrote. "He is not just disrespectful but entirely wrong.
"It was not the club but Mark Hughes who lacked the courage and ambition to take on the task of leadership. If people are looking for a flop, they only have to look no further than the man who has lost his spark."
Al Fayed, the former owner of London department store Harrods, said Hughes walked out on the club after just a year in charge on the day he had agreed to sign a two-year extension to his contract.
Al Fayed said plans for a new stand at Craven Cottage contradicted the Welshman's depiction of the club.
"What a strange man Mark Hughes is," Al Fayed said. "Sacked by Manchester City, he was becoming a forgotten man when I rescued him to become manager of Fulham Football Club."
Elsewhere, Aldershot, the lowest-ranked side left in the Carling Cup, could face the full force of a Manchester United backlash when the teams meet in the last 16 tonight.
United were humbled 6-1 by Manchester City at Old Trafford in the Premier League on Sunday. Alex Ferguson, the manager, has challenged his players to bounce back when they visit Aldershot, who are languishing in 15th in the fourth tier of English football.
"That kind of defeat will make an impact on the players," Ferguson said. "There's a lot of embarrassment in the dressing room and quite rightly so. Hopefully they'll show that [reaction] next week."
Chelsea visit Everton and City travel to Wolverhampton Wanderers tomorrow in two of five all-Premier League games, but the most intriguing match-up takes place at The EBB Stadium.
Aldershot, managed by the former Bolton Wanderers striker Dean Holdsworth, have never progressed so far in the Carling Cup.
"On Tuesday night, we've probably got the biggest game in the club's history," Holdsworth said. "It could mean financial security for a long, long time."
Meanwhile, Javier Hernandez, United's Mexican forward, signed a new five-year deal yesterday. The 23 year old was initially signed from Chivas in July 2010 only as a long-term prospect, but scored 20 goals in his debut season.
"The last player I remember making an impact as big and as quickly as Javier is Ole Gunnar Solskjaer and he reminds me of Ole a lot," Ferguson said.