He was a record-breaker while still a teenager, stringing together 23 straight match wins for the second-longest winning streak by a teenager in the Open era. Only Rafael Nadal had done better.
He already had a Major to his name: the US Open, won while he was only 20.
By the end of 2009, he had reached the final of the World Tour Finals and had a tally of seven titles.
He had become a fixture in the top five, residing amongst the elite since the spring of 2009, and had evenÃ¢â‚¬â€very brieflyÃ¢â‚¬â€crept up to No4.
And then came the 2010 Australian OpenÃ¢â‚¬â€three unexpectedly tough wins followed by a five-set loss in the fourth roundÃ¢â‚¬â€and thatÃ¢â‚¬â„¢s where everything ground to a halt. The young man from Tandil injured his right wrist to such an extent that rest and rehabilitation failed to cure the problem. He underwent surgery last May.
When Del Potro attempted his return to the tour last autumn, there was more bad news. He lost in the first round of two straight eventsÃ¢â‚¬â€in Bangkok and in TokyoÃ¢â‚¬â€and called it a day for the rest of the year.
But this likeable, reticent champion is on his way back, and heÃ¢â‚¬â„¢s doing it in style. Not content with a gradual return to the tourÃ¢â‚¬â€a softly-softly approachÃ¢â‚¬â€he got his eye in with some useful matches in Australia and then headed to North America.
First he hit the indoor hard courts of San Jose and worked his way to the semi-finals. The next week, he was in Memphis and another semi-final. Then in a third consecutive week, he made his tournament debut in the Floridian heat of Delray Beach, and won his first title of the year: indeed, his first title since that US Open 18 months ago.
The style in which he did it was gutsy. Against the top-ranked player, world No17 Mardy Fish, Del Potro conceded just six games.
He then faced the Serbian, Janko Tipsarevic, and looked, when he went 1-4 down in the first set, as though his intense schedule had caught up with him. But he gradually adapted to the differentÃ¢â‚¬â€and difficultÃ¢â‚¬â€conditions of his first outdoor, daytime match in the three North American tournaments.
He pulled the set level, saved five break points in the 10th game, and finally converted his own third set point.
In the second set, he broke Tipsarevic to go 3-2 up and fought off three more break points in the next game. It took him the better part of two hours, but he eventually won the match, 6-4, 6-4. He did so without dropping a set nor reaching a tie-break.
The great news for Del Potro is the impact of this run on his rankings. So low had he dropped that he had to enter these events as a wild card. At San Jose, with his protected ranking at an end, he was down at 484. By Memphis he was up to 298. By Florida, he had clambered to 166. This week, he is back in the top 100, at 89.
His rise through the rankings can continue to surge because he has no points at all to defend for the rest of the year. It could be the work of just a few months to put on the 1000 or so points that would catapult him back inside the top 20. Once there, he can benefit from seeding, avoid the big names until deep into the draw, and pick up still more points.
There appears, though, to be something a little different about the Del Potro embarking on what seems like his second career on the tour.
No longer does he sport the shapeless, ill-fitting, unflattering vest and long droopy shorts of a year ago. He has reinvented himself, in true Nike tradition, in a sharp, shaped, sleeved T with slim, black shorts. Everything, from bandana to sweats to footwear, matches to the nth degree. It is nothing short of the transformation that fellow Nike aficionado underwent at precisely the same age: 22.
Nadal opened his 2009 season ready to take on a new image. He discarded his near-iconic sleeveless vest and pirate pants in favour of striking, striped polos and matching accessories. He had just completed a season in which heÃ¢â‚¬â„¢d won his first non-Paris MajorÃ¢â‚¬â€WimbledonÃ¢â‚¬â€and had reached No1 for the first time, and he wanted to dress the part. It was less a statement on his ability, his impact, his looks or his success and more a statement about his perception of himself: it was confident.
The transition of Del Potro may be the outward expression of a similar Ã¢â‚¬Ëœgraduation.Ã¢â‚¬â„¢ By adopting NikeÃ¢â‚¬â„¢s unselfconsciously titled Ã¢â‚¬ËœFearless Rafa Fuego CrewÃ¢â‚¬â„¢Ã¢â‚¬â€or something very like itÃ¢â‚¬â€the Argentine is standing tall, in flame orange, happy to be noticed, and that is some distance from the 20-year-old Del Potro almost overwhelmed by the new-found fame that accompanied his US Open triumph.
Del Potro was the youngest player in the top 200 in 2005Ã¢â‚¬â€17; the youngest in the top 100 in 2006Ã¢â‚¬â€18; the youngest in the top 50 in 2007Ã¢â‚¬â€19; and the youngest in the top 10 in 2008Ã¢â‚¬â€20. He always looked and played older than his tender years.
Now he begins to look his age. Now he looks, put simply, happier in his skin.
Ã¢â‚¬Å“My goal at the moment is to improve my game day by day,” he said after Delray Beach. “It was my goal to be No1 two years ago, but I donÃ¢â‚¬â„¢t know if I can put that as my goal again because I donÃ¢â‚¬â„¢t know how far my level can go.Ã¢â‚¬Â
Well to the outside observer, it looks as though the re-launched Del Potro can go just as far as he did at 20, and perhaps further. And maybe he will start just where he did back then: in New York.
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BIOGRAPHY: Marcus Rashford