The coach was dismissed by the Rojiblancos at the tail end of last month and was promptly replaced by Diego Simeone but he believes he should have been kept on
After constant speculation about his future, the 55-year-old's departure was finally confirmed after a shock Copa del Rey loss to Albacete just before the winter break.
Manzano insists that he bears no grudge against Atletico but is adamant that he was poorly treated, believing that with the club 10th in La Liga and in the last 32 of the Europa League, he deserved another deal.
"I have no hate in my life for anything or anyone but I deserved a new deal,” he told El Larguero.” I always have gratitude to all my teams but it is true that I had difficult times.
“We could have parted company in a much more ethical and gentlemanly manner."
Manzano was particularly incensed by the behaviour of Atletico CEO Miguel Angel Gil Marin, who reportedly failed to inform him of his dismissal.
“I would be lying if I said that did not hurt,” he confessed. “Professional relationships are not removed from human relationships.
“I served with all my strength and heart and did well until the last moment - I have a very clear conscience.”
Manzano, though, could not resist biting back at Atletico president Enrique Cerezo, who claimed after last weekend’s 0-0 draw with Malaga that the attitude and work rate of the players had already improved under new coach Diego Simeone.
“I do not know if the players ran more or less,” he mused. “But Atletico had much less possession than Malaga and when you do not have the ball you have to run more."
Meanwhile, Manzano also denied that his relationship with winger Jose Antonio Reyes, who has since moved to Sevilla, had completely broken down before his own exit.
"I did not have any problems with Reyes,” he insisted. “I wish him the best at Sevilla and, for us, he was a key player in the early part of the season.
“Jose Antonio has a good heart but I looked to another player, Adriano, who provided more efficiency and goals."