The Ghana international had an impact on both first-half goals scored by Antoine Griezmann and Saul Niguez, earning praise from Atletico head coach Simeone.
"I liked Thomas today. He and Rodrigo [Hernandez Cascante] were great," Simeone told reporters.
"I think he's improving, Thomas is an amazing player. He could have played for Manchester City [or] Manchester United.
"We're talking about a great player here. I rate him very highly."
The midfielder had been linked with a move to Man City ahead of the January transfer window, with Pep Guardiola believed to be in the market for a replacement for Fernandinho.
Thomas has scored two goals and recorded three assists in 18 La Liga matches for Atletico this season.
The Rojiblancos are just two points behind Barcelona in the league following their victory against Getafe and will hope to maintain the pressure on the Catalan club into the second half of the season.