Antonio Conte’s charges travel to Spain to take on Atletico at the Wanda Metropolitano Stadium on Wednesday night, in a game that Cahill believes will be one of their most challenging in Europe.
Chelsea did not qualify for last season’s Champions League, and Cahill is determined to prove that the Blues should be regarded as one of Europe’s elite clubs.
He told Standard Sport: “This is going to be one of our hardest games in the Champions League. It doesn’t get much tougher, so if we can get a result there it will say a lot.
“This is a proper tie. We are not just coming up against technicians and people who are really good on the ball, but they are real men, physical.
“They have the attributes you are looking for in a team. They tick most of the boxes.
“We know a lot about Atletico. We have seen them in European competitions in recent years. They have done very, very well and there is a reason for that.
“It’s going to be a real challenge but we got a draw over there in the first leg of the semi-final in 2014, which we thought had set us up great for the second leg, only to lose. It is important we come back with something.”