John Terry admitted Chelsea put in a disappointing performance before Eden Hazard's stoppage-time strike allowed them to sneak into the last 16 of the Europa League with a 2-1 aggregate win over Sparta Prague.
Holding a 1-0 advantage from the first leg in the Czech Republic, Chelsea were strong favourites to advance but David Lafata's 17th-minute strike changed the complexion of the match.
Chelsea poured forward but allowed Sparta to create chances on the counter-attack before Hazard's late goal levelled it on the night to spare Chelsea's blushes.
"It was disappointing, the way we started, but we're delighted to go through," Terry told ESPN.
"We left it as late as we could as sometimes that's the best way. It wasn't our best performance but we're in the next round and we're happy with that.
"It was a great goal from Eden. The manager's rested a couple and to have the likes of Eden on the bench is great. When he came on he showed great sharpness.
"But they had two counter-attacks in the last five minutes and that's not good at all. We're disappointed with that. It's not the best but we're through."
However, Terry believes Chelsea showed good spirit to keep fighting and deserved their reward.
"We've kept going and going and going," he said. "The first 80 minutes, nothing went for us. We had a lot of attempts on goal but it didn't go for us. But the persistence from the lads was fantastic.
"We're still very disappointed to be out of the Champions League and watching that on Tuesday and Wednesday nights is frustrating but this is a good competition and we're in it to win it."