Nadal who crashed out of the US Open in the third round to Fognini, says he tried to fight back and he lost that battle.
Nadal was up by two sets against his Italian opponent, before Fognini won the next three sets in a thrilling match 3-6 4-6 6-4 6-3 6-4.
This will be the first time since 2004, that Nadal will finish without a grand slam, but the world no 8 insists he tried his best.
“I fought until the last point but I didn’t do enough to win and I’ve lost a lot of matches this year like this,” Nadal said.
“My mind allows me to fight to the end and sometimes in my career I haven’t been able to do it.
“The crowd was amazing and the support I got gave me a very special feeling. I enjoyed that and I tried to fight, I believe I did.
“But it was not enough. The only thing that means is I played worse than the last 10 years.
“That’s the real thing. By the way, for me it was amazing to win a grand slam 10 years in a row. I think nobody did. You can imagine how difficult it is to make that happen.
“I accept this was not my year and keep fighting till the end of the season to finish in a positive way for me.”