Atletico made a poor start to La Liga, resulting in the sacking of manager Abel Resino, but will finish the campaign in mid-table and with a European trophy.
They have also reached the final of the Copa del Rey and Sanchez Flores is delighted by the way the club's season has been transformed.
"I am really proud of my players. They deserve all the credit because they were able to overcome a complicated situation," he said. "I can only stress my admiration for the work they have put in to turn our campaign around.
"It has been a long, hard season and that makes this success even more special.
"There are a lot of emotions that come out after an achievement like this.
"But I would like to dedicate this triumph to my four children and to Atletico fans everywhere."