Ronaldinho claims Manchester United would have been more successful in the Champions League had the Brazilian secured a transfer from Paris Saint-Germain in 2003, rather than sign for Barcelona.
The 32-year-old was strongly linked with a move to Manchester United in the summer transfer window almost 10 years ago, but Barcelona won the race for the signature of the coveted Brazilian.
Ronaldinho was twice named FIFA World Player of the Year during his five seasons at the Camp Nou to reinforce just what Sir Alex Ferguson had missed out on by failing to bring him to Old Trafford.
The Brazil international, who faces England at Wembley on Wednesday, does not regret signing for Barcelona over Manchester United, although joked that the Red Devils would have been more successful had he made a different decision.
"Yes, that was the only time it has been a real option," Ronaldinho told the Daily Mail when asked if he could have joined the Red Devils.
"If Manchester United had signed me they would have won more European Cups!"
The one regret Ronaldinho does have, though, is the failure to play in the same Barcelona side as Lionel Messi for as long as he would have liked, with the latter flourishing since the Brazilian's departure.
"The only regret is not playing more seasons with Lionel Messi," he added.
"He is my good friend. I could see even at a young age he was going to be the best. It was exciting to see this kid who could do things most players can only dream of."