Sydney: Wrist surgery, depression and the terrifying feeling that his career was about to prematurely end. With a ranking which plummeted to 485 in the world, pessimism swirled around Argentine giant Juan Martin del Potro last year before he mounted a scorching comeback that has him bursting with confidence and renewed belief ahead of the Australian Open.
Del Potro pulverised Poland`s Lukasz Kubot 6-4, 6-2 on Wednesday to reach the quarter-finals of the Sydney International, and continue homing in on the untouchable form that won him the U.S. Open title in 2009, when his fifth set against Roger Federer was as commanding as tennis can be.
He was on the up back then, number four in the world and rising, but wrist surgery in 2010 wiped him off the tour for eight months. He spent most of that time worried his career was over -- he openly admitted at the time he was "depressed" -- and that even if he did make it back on tour, he would never again scale the heights.
That pessimism has been replaced by unbridled optimism, however.
Del Potro combatted strong winds and stiflingly hot Sydney weather to account for Kubot and set up a quarter-final against Cypriot Marcus Baghdatis.
One of the few men to beat world number one Novak Djokovic last year, Del Potro looms as one of the dangermen of an Australian Open headlined by Djokovic, Rafa Nadal, Roger Federer and Andy Murray. His ranking has gone from 485 to 11 in less than a year.
"To beat these kinds of players can be a big goal for this year," del Potro said. "I`m working for that. This time last year I was really scared, basically in this tournament, in Australia, because it was my first tournament after the surgery.
"But with time and practising and trying to think about things other than my wrist, I improved a lot. I won matches, and that`s helped me to keep the confidence I can be healthy and play better. At this moment, I don`t think of my wrist, so it`s a good signal for the future."
The fine print to Del Potro`s win over Djokovic in September was that the Serb retired when trailing 7-6 3-0 in the Davis Cup semi-finals. Still, Del Potro was heartened by going toe-to-toe with the world number one for two straight sets.
Have no doubt that Djokovic and the rest of the upper echelon are fully aware that a fit and firing Del Potro is a frighteningly real threat to them all.
It was the Argentine`s loss to Nadal in a four-set thriller at Wimbledon last year that triggered the most significant leaps in confidence and renewed belief.
"I have many good memories of last year but maybe the match against Nadal at Wimbledon was the best match of the year, for me anyway," Del Potro said.
"Novak, well, he retire, but I was playing a really good game against him. We were the same level in the first and second sets. Then he retire, but it was a nice memory for Argentina.
"It could be a big challenge for me to win a major this year because I think I`m still far from that goal. But I`m working hard and feeling good every day. I need time to do it step by step and then be ready for that moment when it comes.
"To reach the second week of the Australian Open would be a good start to the year."