Jose Mourinho's side has a two-goal deficit in the Champions League quarterfinal after conceding in stoppage time at the Parc des PrincesGary Cahill admitted the late Javier Pastore goal in Chelsea's 3-1 defeat to Paris Saint-Germain was a 'devastating' blow.
PSG took the lead at the Parc Des Princes through Ezequiel Lavezzi, but Chelsea pulled level through an Eden Hazard penalty.
But a David Luiz own goal put the hosts back in front, before Pastore beat Petr Cech at his near post at the death to give his side a huge boost ahead of the Champions League quarterfinal second leg at Stamford Bridge.
"[It was a] horrible time to concede then, a sloppy goal, unlike us and it was a big blow at 2-1," Cahill told Sky Sports.
"Obviously it was difficult to come here. 2-1 would have been okay going back to Stamford Bridge I suppose, but the blow at the end is devastating."
Cahill remains optimistic that Chelsea can still win the tie at Stamford Bridge, despite the two-goal deficit.
He added: "It will be tough but we're at home at Stamford Bridge and we've been playing well there.
"We need to, we've got a big task ahead of us and we need to approach it in the right manner and be on the front foot, but obviously a disappointing night for us."