Deco admits he feels happy again at Chelsea and believes he made the right decision to stay at the club over the summer.
The Portuguese playmaker moved to Stamford Bridge in 2008, bringing with him a glowing reputation following trophy-laden spells at Porto and Barcelona.
He was lured to England by his former international coach Luiz Felipe Scolari, but the Brazilian failed to see out the 2008/09 campaign in West London.
Deco made a bright start to his debut season in the Premier League, but niggling injuries and a loss of form soon saw him slip down the pecking order.
He was regularly overlooked by interim coach Guus Hiddink and his days at Chelsea appeared to be numbered.
Various reports over the summer suggested he was set for a switch elsewhere, although nothing materialised.
Deco has instead knuckled down at Chelsea, after holding talks with incoming boss Carlo Ancelotti, and has re-established himself as an integral part of the Blues' first-team squad.
"Last season was the worst of my career because I had never had so many injuries before," he said.
"When you are not in the side you think about things such as leaving because of what might happen the following season.
"This season things are different. I know I am well and fit and I can play. I want to help the team and I think Carlo Ancelotti trusts me.
"When he arrived we spoke and he told me he wanted me to stay. I needed that and I am now enjoying that decision."
Another Chelsea star thankful to Ancelotti for reigniting their career is 17-year-old centre-half Jeffrey Bruma.
The Holland U21 international is tipped for a bright future with the Blues, but had failed to make the breakthrough under previous regimes.
Ancelotti, though, handed him a senior bow in Saturday's 5-0 mauling of Blackburn and the Dutch youngster is grateful to the Italian for showing faith in his ability.
Bruma, who joined from Feyenoord in 2007, said: "Carlo Ancelotti sent me on telling me to enjoy myself.
"He has a warm personality and always has time for the younger players.
"Since I've been in London I've seen managers who never said anything to the youth-team players."