The Gunners were unable to hold on to their 2-1 lead from the first leg and were eventually eliminated 4-3 on aggregate by the Spanish giants, and have fallen by the wayside since
The Gunners beat the Spanish club 2-1 in the first leg at the Emirates but a stray pass from the Spaniard set in motion the first of Barcelona's three goals at Camp Nou, with the Premier League side ultimately dumped out of the competition 4-3 on aggregate.
He told Don Balon: "The second leg at Camp Nou was one of the most important games of my career. I was returning to Barcelona as Arsenal's captain, with a favourable result from the first leg, playing against friends and with my family in the stands.
"We had high expectations ahead of the game, but it ended in disaster and I was the one to blame. I'm 70 per cent responsible for Arsenal's Champions League exit."
The Spain international added that he wasn't fit enough to play for the full 90 minutes and should have asked for a substitution.
He continued: "I picked up a knock after 14 minutes and my world just collapsed when I looked at the clock and saw that we were only a quarter-hour under way.
"I did already miss the Carling Cup final as I was rested and I didn't have any problems ahead of the match against Barcelona.
"I picked up a hamstring problem though when I intercepted a pass from Adriano. I've had this injury before and I told myself not to give up. If I had left the pitch them, which I should have done, I'd have regretted it for the rest of my life. People would have thought that I didn't want to play."
Fabregas went on to say that he decided to stay on the pitch, even though the injury prevented him from playing his usual game.
"I really wanted to continue play, even though I could hardly turn and couldn't sprint," he said. "I suffered a lot out there and then came that one ball.
"I'm not the type of player to shoot the ball out of play in a difficult situation. I didn't know what to do and eventually lost the ball to [Andres] Iniesta, who set up [Lionel] Messi for the goal."
The former Barcelona youngster admitted that it would have been better for the team had he been substituted.
He added: "I was really disappointed with myself. I really wanted to play and didn't thin about the team's interests. I was selfish and ended up paying the price as I didn't play well and we lost.
"It also hurt my family to see me like that and they immediately knew something was up. It really was a day to forget, but I've learned from my mistake."
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