The former West Brom midfielder has failed to hold down regular first-team football with the Cottagers this season, but emerged off the bench at the weekend to help secure a famous victory over the Red Devils.
Gera had scored just twice for Fulham this season before teeing himself up to volley home Andy Johnson's inside ball to secure an unlikely 2-0 success over Sir Alex Ferguson's side on Saturday.
The 29-year-old acknowledged he has scored other crucial goals in his career, but after going without a goal in England since September, says the effort could not have come at a better time.
Most important"This was the most important goal of my career," he told Pepsifoci. "I've scored some momentous goals for my previous teams but this was very important for my own career.
"In my present situation this has happened in the best moment and not against just any Premier League team but against Manchester United.
"My self-confidence needed it very much and I also needed it for the forthcoming international games with Hungary and for the Fulham fans who haven't seen me impress on the pitch so they don't know what I'm really capable of.
Role won't change"On Saturday I showed a bit of my abilities. I know I won't be in the line-up just because I scored this goal and this won't change my role in the team.
"I'm not even thinking about Fulham's next game because there's a two-week break because of the international matches and many things can happen during these days.
"But a lot has changed inside me now. I can again believe that I can play well and score a goal like this. I'm very happy about it."