The Blues were cruelly defeated 2-0 as two Branislav Ivanovic mistakes both resulted in easy goals for the visiting Swans at Stamford Bridge.
Cahill still believes that the tie isn’t dead, offering up examples of games against Napoli last season to emphasise Chelsea’s mental toughness.
“It is never over. We created enough chances to go in at half-time three-nil or four-nil up,” he said.
“And if we take those chances in the away leg and keep it tight, we will win.
“It will be difficult because I’ve certainly found it tough when I’ve been to Swansea on my last three visits. I got two draws with Chelsea and lost with Bolton, so it is a difficult place to go.
“But we showed we can turn it round when we did it against Napoli in the Champions League last season, so this team can do it – and we need to.
“I think if we had taken our chances we would have won convincingly and there is no doubt we can create chances there,” he continued.
The loss against Swansea left the player a little bemused in light of recent form. The Blues began the game with eight wins from 10 matches.
“Normally, we are unbelievably hard to beat at Stamford Bridge and we’ve been getting results,” said Cahill.
“We’re having all the possession, but it counts for nothing unless you create a lot. In the first half against Swansea we created chances and if you take one or two they have to come out.”