Tosic was signed along with Adem Ljajic from Partizan Belgrade and whilst both were regarded as hot prospects, United cancelled their deal to sign Ljajic whilst Tosic made a handful of appearances, mainly in the cup competitions, before going on a successful loan to Cologne.
But upon returning to Manchester and seeing no improvement in his situation, Tosic decided to move permanently to CSKA Moscow after just 18 months at Old Trafford.
Now returning to Britain with Serbia ahead of their World Cup Qualifier against Scotland, the diminutive winger 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.”