A victory in their last group match will ensure first place for England, while a draw will also be enough to finish top if Wales fail to beat Russia in the other game.
Top spot would mean England face a third-place finisher in Groups A, C or D, while second would mean they took on the runners-up of Group F.
"To top the group gives us the best opportunity to move forward in the competition," the defender told FATV.
"So that is our goal and we are all aware of that. We want to finish top and we feel that we are good enough to do that - we just need to prove it against Slovakia.
"They need a result to stay in the competition as well and we know it's going to be a hard game."
After conceding a last-minute Russia equaliser in their first match, Cahill felt England deserved the stoppage-time winner scored by Daniel Sturridge against Wales last time out.
He added: "We feel that we have been playing well and we felt hard done by in the first game because we did play well in that game.
"Football can be a cruel game sometimes but I thought we got what we deserved in the Wales game, even though it came late.
"I wouldn't say I prefer to do it like that but when it happens like that it is special. The atmosphere in the stadium was unbelievable."