After losing in a third set tiebreaker to Novak Djokovic in the Shanghai final, Juan Martin del Potro says his form is even better than when he won the 2009 U.S. Open, beating Rafael Nadal and Roger Federer in succession.

In the past two weeks, del Potro beat Milos Raonic in the Tokyo final, upset Nadal in the Shanghai semifinals and qualified for the ATP World Tour Finals.

“I think I’m playing even better than 2009 or 2008 or last year,” del Potro said. “That’s important. That’s a good thing for the future. I’m still having the same goal, which is getting closer to the top guys… Not many players have the chance to beat them. I always believe on myself.  It could be my biggest challenge of my career, getting closer to the top positions. But also I am very clear they are playing so solid for a year, and I played good tournaments. I think there is the difference between the top guys and me or the rest of the players. I have to be playing in this level for many, many tournaments in a row, or in important tournaments.”

Del Potro, who was struggling with left wrist injury during the summer, said his wrist appears to have healed, which is why he is able to crack his two-handed backhand again. At the U.S. Open, del Potro was forced to play one-handed slice backhands.

“I hit 100 percent my backhand. I remember the match against [Nadal] in Indian Wells. I played too many slices because my wrist," del Potro said. "Today I feel 100 percent physically. That's what I need against these players.  My backhand is starting to work good again. I feeling confidence with my wrist. That's important because I can use all my shots.”