Lionel Messi fought back tears during a press conference on Sunday at which he confirmed he is leaving Barcelona, where he has played his entire career.
The 34-year-old Argentinian superstar, six times a Ballon d'Or winner, has been out of contract since the end of June and Barca say they cannot afford to keep him, with Messi admitting that a move to Paris Saint-Germain is a "possibility".
"I have still not come to terms with the reality of leaving this club now, changing my life. I love this club."
Last year he sought to engineer a release from his contract in frustration at some poor showings in Europe by the club where he has won four Champions Leagues but ended up staying.
Last year, he explained, "I was convinced I knew what I wanted say, but this year is not the same", stressing his preference was to prolong his stay rather than contemplate what now seems a likely reunion with former clubmate Neymar at PSG -- ostensibly the only club that can afford him with Manchester City having distanced themselves.
He hotly denied asking for more money but had, on the contrary, accepted a 50 percent salary cut.
"I would've liked to have won another Champions League," he added while stressing that "I don't regret anything, I tried to give my best and I'm ending my career here with a good number of titles".
"The truth is I don't know what to say," said Messi, who signed for the Catalan giants as a 13-year-old.
"After 21 years I am leaving with my three Catalan Argentine children," said Messi, who won 10 league titles with the club.
"I gave everything for this club from the first day that I arrived right to the last. I never imagined having to say goodbye.
"In recent days I have given lots of thought to what I can say and truth to tell I can't think of anything.
"This is really difficult for me after so many years spent here -- my entire life. I'm not ready for this," he said.
"We have had some good times, some bad times too -- but people always showed me the same love," said Messi, who said leaving was "sad and hard."
As thousands of Barca fans milled outside in disbelief at his exit, Messi told reporters one day he hoped to be back in some capacity.
"I hope I can come back and be part of this club at some moment, in any way and bring something to help this club to be the best in the world."
Messi was at pains to say that "nothing has been signed with anyone" and insisted that a picture of him which has made waves on social media in recent days of him on holiday with PSG stars including Neymar and Angel Di Maria was "just a photo".
He said there was no question of his having engineered a path to the Parc des Princes, adding that there had been interest from other clubs.
"When the press release (of his departure) was published, I received a lot of calls from interested clubs," he told reporters who applauded him for several minutes as he took the stage at the start of the press conference and again as he left the stage to embrace staff in the club's trophy room.
"For the moment nothing is arranged but, yes, we are in discussion," said the Argentinian, who insisted he has always been "totally transparent" on his intentions.
According to Le Parisien, an agreement between PSG and the Argentinian could take place as early as later on Sunday.
French sports daily L'Equipe forecast a "record contract" of three years, "with an annual net salary of 40 million euros".