The Brazilian-born striker was the catalyst yet again for another Rojiblancos victory and his coach and colleagues are only too aware of the importance he holds for the side.
The Brazil-born attacker netted his 13th Liga goal of the season as the capital club saw off the Basques and moved one point behind first-placed Barcelona.
Simeone feels his star player has grown in every way recently, helping the rest of the team to its fantastic start to the season.
“Diego is huge in every way,” the Argentine told reporters after the game. “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.
“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.”
Teammate Diego Godin also spoke about the 25-year-old in glowing terms, highlighting the work rate of Costa and his strike partner David Villa as one of the main reasons behind Atleti’s fine form.
“Diego Costa and Villa are really good up front,” he said. “Their goals are very important, but they are also very involved in the defensive side of things. They come back to help the defense often.”