Asked directly whether the 35-year-old Frenchman is the best player he has worked with, Simeone paused — prompting a playful jab from Griezmann himself — before giving his verdict.
"Yes, I'm grateful to have had such a game-changing player," the Argentine told reporters. "He arrived running down the wing, went through three difficult months to understand where he was.
"I told him I saw him playing more centrally, with incredible mental energy. Then, many times he scored the most goals of the season. He's one of the best I've ever had, yes."
On Griezmann's imminent departure — confirmed last month when Orlando City announced his signing for the 2026 MLS season — Simeone was characteristically private.
"There are conversations that aren't talked about. We've spoken quite a bit, he told me how he felt, I understood it because of the game."
The timing gives Wednesday night's first leg an added emotional charge. Griezmann has 210 goals for Atlético in total, making him the club's all-time leading scorer by some distance, surpassing club legend Luis Aragonés. He scored his 200th in a 5-1 Champions League win over Eintracht Frankfurt in September — then, just days earlier, had scored in a stunning 5-2 derby victory over Real Madrid. At 35, his influence has waned this season but his place in the club's history is unassailable.
Atlético head into the quarter-final in poor form, having lost three consecutive matches, and face a Barcelona side seven points clear at the top of La Liga. The sides met only four days ago, with Robert Lewandowski's late goal giving Barca a 2-1 win at the Metropolitano. Simeone rotated heavily that day with Wednesday in mind — and will need Griezmann at his best if Atlético are to spring a surprise at Camp Nou.