The 25-year-old, who has quickly emerged into one of the best forwards in Europe, has scored 13 league goals for Atletico during their impressive start to the season.
"Diego is huge in every way. On top of the goal he scored today, he is growing as a player – he is more of a team player and helps us win the ball back," Costa told reporters at a press conference.
"All of that makes the whole team play better. We hope he continues to grow because he's got many years ahead of him to get even better."
Atletico currently sit second in La Liga, one point behind leaders Barcelona.