Ferguson sprang a major surprise when he confirmed Larsson as a short-term arrival during the 2007 January transfer window - and the striker made an instant impact at Old Trafford.
Although he only scored three goals in 13 matches, the now 39-year-old Swede made a significant impact on the Red Devils' performances during a difficult period of the season and ended the campaign with a title medal after special dispensation was granted by the Premier League.
Yet he also ended it back home in Sweden, having refused to go back on an agreement to return to Helsingborgs for the start of their domestic programme.
Yet now, at the start of a coaching career with Landskrona he never gave any indication of wanting to pursue, Larsson has acknowledged he made a mistake when he said no to Ferguson.
"If there is one regret I have from my career, it is that I came home to Sweden when Mr Ferguson was trying to get me to stay at Manchester United," Larsson told fifa.com.
"I should have stayed at United for longer because I had a great time there and everyone at the club was very keen to keep me. My time there was too short.
"The whole experience was fantastic and, although I was 35 at the time, I still felt that I had some good football in me. That is a regret."