Lionel Messi put a pair of shots through Courtois' legs, with Ousmane Dembele adding another goal as Barcelona cruised to a 3-0 win to advance to the quarterfinals 4-1 on aggregate.

While Courtois did not take full blame for the result, he said he should have done better to stop Messi's opening goal, which came just 128 seconds into the game.

"I don't think we deserve to be out, but individual mistakes cost us in both legs," the Belgium international told BT Sport.

"The first goal, I did not expect Lionel Messi to shoot from that angle and I was too late in closing my legs. It was a mistake on my part.

"There were missed passes from us and they scored from our mistakes. We defended and played well, hit the crossbar which was unlucky on our side, but the individual mistakes cost us. We have to be honest about that.

"I played against Messi a lot of times, I have already conceded goals like that before. The weakest point is between the legs for a goalkeeper.

"It is annoying, I cannot hide inside -- I have to be a man and come out.

"I made some good saves too, but we go out with conceding four goals from four mistakes."

Chelsea midfielder Marcos Alonso said he thought his side "were a little bit unlucky" to concede early and had squandered opportunities to get back into the game.

"They have Lionel Messi and I think they were the better team even though we competed well in both games," Alonso said.

"If we concede easy goals and miss chances, then it is very difficult against this team.

"We know they have top players and we cannot give them one metre because they can create and score.

"We were a little bit unlucky with the first two goals, we hit the post three times and had so many chances in both games. We have to improve and, when you lose, you have to train and get better.

"They were not comfortable in the first half and we just missed the chances. It could have been 2-2 at half-time but, at 2-0 in this stadium against this team, it is not easy to come back."