Zoran Tosic admits he was too hasty to turn his back on Manchester United after finding his route to the first-team blocked.
The Serbia international was snapped up by the Red Devils in a £7million deal from Partizan Belgrade in 2009.
He arrived at Old Trafford with a big reputation and was billed as a potential Premier League star of the future.
United, though, were keen to ease him into English life and he made just two senior appearances during his first year with the club.
A loan spell at Cologne followed, before Tosic left for CSKA Moscow after just 18 months in England.
He now concedes that he should have stuck it out at United and waited for an opportunity to impress.
Ahead of the 2014 World Cup qualifier against Scotland on Saturday, the 25-year-old forward told the Daily Record: "It all happened really quickly as I played for just 18 months with Partizan Belgrade.
"We won the league and the cup and there was a period when it seemed like I was scoring in every match.
"It was at that point I signed for Manchester United. It was such an exciting moment to go there and to meet Sir Alex (Ferguson).
"I had grown up as a United fan so to be working for the man who had brought so much success to the club was just unbelievable.
"However, there is a big difference between the Serbian and English league and when I arrived in Manchester I discovered I was not yet ready for that level.
"I spoke with Sir Alex many times and he kept telling me I had quality and just had to keep working hard.
"But I wanted to play more games so went to Cologne in Germany on loan and had a great six months there.
"When I came back to Manchester I was expecting to play more games for United but it didn't happen.
"In the end I wasn't sure I was going to get the chance I felt I deserved so decided to change club. Even now I am always thinking about that moment. Maybe I shouldn't have been so quick and should have worked longer to show Sir Alex.
"Maybe I should have stayed and fought for my place. This was Man United after all."