Rafael Benítez’s side were beaten 2-0 by the Swans in the semi-final first leg at Stamford Bridge – and Cahill knows that the west Londoners must be at their best if they are to overturn the deficit and book their place at Wembley.
“It will be tough because it’s a hard place to go,” Cahill told Chelsea’s website. “They’re so well-organised and play really good football.
“The key for us will be getting the first goal, if we can do that I’m sure it will be a nervy night for them and that’s what we aim to get.
“They’re an attacking team, but we have to go at them and try to hurt them. It’s certainly one of the biggest games of the season for us.”
“We possess the quality to hurt teams, but consistency will be the key for us,” he added. “Sometimes we’ve dropped points in games we would expect to win.
“We just have to keep looking upwards, we need to make sure we’re in the Champions League places for next season and obviously we’re still in three cups.
“We just need to keep trying to win games. We’ve already seen this season that teams can slip up here and there, so we need to win as many games as we can and see what happens.”