Lawrie Sanchez claims Fulham have gone backwards since they sacked him in December.
The 48-year-old quit his job as Northern Ireland manager to oversee Fulham’s rebuilding after narrowly steering them clear of relegation last season.
Sanchez spent £26.5million overhauling the Cottagers’ squad but had his contracted terminated on December 21 after a run of poor results.
He believes he was not given enough time for his new players to gel and added that his successor, Roy Hodgson, has only taken them further into the relegation zone.
He said: “The reason I was appointed was because the team had won only two games towards the end of last season. It was not as if they were flying high. Fulham thought they were going to get relegated but I came in and got them the points to keep them up.
“Having dropped into the bottom three for the first time I was then sacked having changed players – 15 in and 15 out. Any sensible person will tell you it takes time for a team to settle. Why undertake the rebuilding of a team if you are not going to see it through?
“But the nature of the Premier League is such that if you go into the bottom three, the manager is sacked. The pressure builds up to a point where clubs think they need to make changes.
“The ironic thing is that I was sacked when they were one point in the relegation zone and now they are five points from safety.
While Sanchez struggled to impress the Fulham board, his reputation with Northern Ireland had soared after wins over England and Spain.
He took the international minnows up 91 places in the FIFA world rankings to 33rd, but he left the job to dedicate all his time to Fulham.
It is a decision which Sanchez regrets and he hopes his reputation as a manager has not now been tarnished. Sanchez, who was speaking at an AFC Wimbledon event, added: “Last May I saved a team from relegation from the Premier League and I was still in charge of an international team at the top of their European Championship group. Then, by December, I am out of work with no job.
“I am disappointed it ended the way it did at Fulham. I am also disappointed I gave up the Northern Ireland job.
“If I had been stronger, I would have done both jobs because at least I would still be considered a quality international manager.
“It is disappointing I only survived for four months at Fulham. I only hope that those few months will not wreck my managerial career.”