COMMENT: Radamel Falcao is facing the biggest challenge of his career. There's no overstating it. The Colombian is battling a crisis which could see him go the same way as Fernando Torres.

This is all new territory for Falcao. Before Manchester United and Louis van Gaal, the 29 year-old's career had been unstoppable.

Yes, there's been serious injuries. But he's overcome them. He knows where to look within himself to slay any doubts and push himself back to full fitness.

But United, Van Gaal and the battle for goals and form is all new to him.

Not since his days as a junior with little Union Magdalena, where Falcao was converted from a run-of-the-mill defender to a striker of real promise, has the 29 year-old had to confront genuine doubts about his game.

From River Plate to Porto, then Atletico Madrid and AS Monaco, the goals and adulation have flowed.

Particularly since leaving River in 2009, Falcao has set goalscoring and transfer records. It's always been onward and upward - every challenge was met and overcome.

But with just four goals to his name this season and serious questions being asked if he's past his peak, Falcao is in the middle of the unknown. It's a situation he cannot draw on past experiences to tackle.

Silvano Espindola, who took Falcao to River as a 15 year-old and remains a long-time mentor, admits the situation at Old Trafford is something his friend has never before experienced.

"It's weird. He's never suffered like this, such a negative streak. It's a new situation for him and everything will depend on how he responds," says Espindola, who remains in regular contact with the striker.

Something similar struck Fernando Torres after his record move from Liverpool to Chelsea.

Before his £50 million transfer in 2011, like Falcao, Torres' career was unstoppable. At Liverpool - and before the days of Luis Suarez - it was Torres who was lauded as the club's greatest modern day striker, a player worthy of being mentioned in the same breath as Kenny Dalglish.

But at Chelsea, where the system wasn't built around his strengths and he struggled to settle, Torres' career quickly nosedived - never to return to its previous heights. At 27, he was facing his first serious bout of poor form and had nothing to fall back upon to drag himself out of it.

As Espindola hints, Falcao is now facing the same situation. Is that real, genuine self-belief still there?

Encouraging for Falcao and his supporters was his recent return with the national team. Three goals in two friendlies against Bahrain and Kuwait saw him draw level with Arnoldo Iguaran as Colombia's all-time leading goalscorer.

And his agent, Jorge Mendes, after calling on his extensive contacts, has at least half a dozen expressions of interest from some of Europe's biggest clubs should United choose to cut their losses in June.

On the training pitch at Carrington, he's impressed both teammates and United coaching staff with his attitude and application. There's been no wobbles over his treatment by Van Gaal, as Espindola states, it's simply not in his nature.

"He never complains, holds no grudges with anyone. He always has the same attitude. I assure you it is a very difficult time in his life, but he still trains every day as if nothing happened. So what if they give him just 10 minutes? He takes the field like it's his last game and does the best job possible. He has a kind of professionalism that suits Manchester United."

It's a professionalism which could rescue his career at Old Trafford.

Ed Woodward, the United executive vice-chairman, has held fresh talks with Monaco about Falcao's situation. The word coming out of negotiations is that United - and Woodward particularly - aren't ready to give up on the centre-forward just yet. If Monaco are willing to re-adjust their asking price, Falcao could stay on.

Along with Angel di Maria, Woodward sees Falcao as the marquee name to establish his relationship with the United faithful and a reputation amongst the elite in the game. And if Falcao can hit 25 goals next season, after he has nicked him away from Monaco for a cheaper price, then all the better.

But everything will depend on Falcao and whether he can shake his bout of 'Torres syndrome'.

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