Roma sporting director Monchi says Atletico Madrid rather than Chelsea are his club's biggest rivals for a place in the knockout stages of the Champions League.
Roma host Atletico on Tuesday while Chelsea are at home to Qarabag in Group C's other match.
Azerbaijani side Qarabag will be Roma's next opponents before their double header with Antonio Conte's Chelsea, but former Sevilla sporting director Monchi said Atletico represent the toughest task.
"We are going to face an Atletico like we have seen in previous years," he told Spain's Movistar Plus. "They work very well.