The hosts were up 2-0 at half-time through a Luis Suarez strike and a Layvin Kurzawa own goal, and Lionel Messi added Barca's third early in the second half from the penalty spot to give hope to those looking for a comeback.

But an Edinson Cavani goal at the 62-minute mark seemed to give PSG breathing room until a Neymar free kick and penalty minutes apart set the stage for Sergi Roberto's miraculous 95th minute goal to complete the rally and send Barca through to the quarterfinals.

Speaking after the match, Emery said: "When we analyse it it is true that we have missed a major opportunity. The first half was our fault and we didn't manage to press or do things with the ball. We defended very deep and they had more chances to score. We made mistakes for the two first-half goals.

PSG players look downcast as Luis Enrique celebrates after the full-time whistle was blown in a 6-1 loss to Barcelona.

"We were calmer in the second half and better positioned. We improved and had a chance for 3-2. The refereeing decisions went against us and we lost everything in the closing minutes. Barcelona are capable of doing that. It was all or nothing for them in the final minutes.

"It's a negative experience for me and for the club. We need to learn from it."

PSG chairman and CEO Nasser Al-Khelaifi tried to put on a brave face after he watched his players and coach be humiliated by Barcelona, but he too refused to make excuses.

"Even if we should have had two penalties, we are not looking for excuses," said Al-Khelaifi after the final whistle. "We did not play in the first half. After winning the first leg 4-0, it is very difficult to accept losing the second 6-1 but we do not have a choice.

"After our first leg win, the aim of reaching the quarterfinals was legitimate, but we know in football that that does not mean anything. We tried to do our best. We did not manage to qualify but we will continue.

"To concede three times in seven minutes when we had been trailing 3-1 after 88 minutes is very hard. I have not spoken with the players yet, it is not the right time. Everyone is annoyed, it is normal. We are going to calm ourselves down."