The Colombian international striker has endured a tough spell on loan with the Red Devils as he bids to win a permanent move to Old Trafford at the end of the season.
After suffering a long-term knee injury last season, many Premier League observers questioned whether the former Atletico Madrid favourite could return to his best.
So far, it has proven to be a difficult task for AS Monaco-owned Falcao as a succession of setbacks this term has restricted him to just eight Premier League starts with five more appearances coming off the bench.
The 28-year-old lacks confidence in front of goal, with his last strike coming on New Year’s Day in the 1-1 draw away at Stoke City.
Former Liverpool man Mark Lawrenson told BBC Sport last week that the Red Devils should steer clear of signing him permanently, but Forlan believes with time Falcao will ultimately prove his doubters wrong.
“To live in England or play in the Premier League doesn’t represent a problem for an intelligent and strong player like Falcao, but he needs to play, he needs minutes,” Forlan was quoted as saying by The National.
“In River, Porto, Atletico and Monaco, he was the best striker but now he has to compete with big names such as Wayne Rooney and Robin van Persie.
“Being on loan will bring more pressure as he’s effectively on a season-long trial and expected to score in every game, but I’m convinced Falcao will come good again, even if it is not at Manchester United. He just needs time and minutes, but trust me, he’s top-quality.”