Asked about Perez, Pellegrini said: "Maybe it looks and you can think he refuses".
However, the forward simply sat on the bench and refused to warm up for his manager who was keen to bring him into the game. "I am anxious about finding the right team to play well and to win the game".
Victory will go a long way to alleviating frustrations in east London after the club lost their opening four matches, and Pellegrini now believes the club can still achieve their objectives this season after the poor start.
"Given the false information spread by the media that has affected my image, I am obliged to explain the only truth: I have never ever refused to warm up in my whole career, let alone play a match".
'The images that have been misinterpreted correspond to a talk with the goalkeeper's coach, in which I never refused to warm up and explained what happened.
'As a professional I accept the decision and will continue working hard to have as many minutes as I can'.
"I don't have to explain the decision, especially during the game, but Antonio was ready so Antonio was the change".
He said: "I was not anxious about my birthday today - I just wanted to win the game - it was the best gift my players could give me".
The Chilean tactician was celebrating his 65th birthday at Goodison Park, and his players certainly provided him with the ultimate present after clinching three vital points, taking the Hammers off the foot of the table and out of the relegation zone.