Unai Emery hit out at referee Deniz Aytekin, Barcelona forward Luis Suarez and an un-named Paris Saint-Germain player as he reflected on the 6-1 Champions League collapse suffered at Camp Nou in 2017.

PSG, then coached by Emery, romped to a 4-0 win in the first leg of their last-16 tie, but on March 8, a day Emery remembers as the worst of his career, Barca recorded an unbelievable second-leg comeback.

Leading 3-1 on the night but still trailing 5-3 on aggregate after 88 minutes, Barca were on the brink of elimination.

However, they managed to score three times in a dramatic finale to seal the largest comeback in Champions League history, with future PSG star Neymar scoring twice for Luis Enrique's hosts.

Reflecting on the devastating loss more than three years later, Emery hit out at the performance of Turkish official Aytekin.

He also discussed his belief Suarez kept going down easily in the box and suggested there was a PSG player who was "hiding" as he explained the other circumstances that worked against his team.

"There are lots of details in that game that can be scrutinised," Emery said, per EFE, in a discussion with his former Sevilla assistant Diego Martinez, who now coaches Granada.

"But if I start from the end, I'd change the referee and that's it. I watched a repeat of the game the other day because I found it while I was zapping through channels. I watched it from the 50th minute to the 82nd minute.

"We were 3-0 down, we scored to make it 3-1 and we had a one-on-one that Edinson Cavani hit at the goalkeeper to make it 3-2; a clear penalty on Angel Di Maria that wasn't given; and in the 82nd minute, Di Maria fouled Neymar for the goal. That's when I stopped watching.

"In that section of the game, I saw that one of our important players, who had had injury problems during the season, was hiding in the result. Maybe I would substitute him now. 

"They are details, circumstances that escape you in a game.

"Then there are other key circumstances: the Barcelona players, especially Suarez, going down in the box continuously, pressuring the referee until he fell into their trap."

Barca were knocked out in the by eventual finalists Juventus in the last eight.