The European champions are preparing for the Europa League winners in Friday night's UEFA Super Cup in Monaco and Cech knows that Diego Simeone's side will be difficult opponents.
"I've played against Atletico before, but since Diego Simeone's arrival in the dugout their playing style has changed," he told Uefa.com.
"They're very disciplined, with an especially solid defence, and are difficult to handle on the counterattack.
"Also, because they're a Spanish team, they all want the ball and feel comfortable on it.
"With this change of style, Atletico are much more dangerous than when we faced them in the 2009-10 Champions League.
"Success has helped them. They are very well-drilled so beating them won't be easy."