Juan Martin del Potro upbeat for final against Novak Djokovic

 Returning to the scene of his prime tennis moment is enough for Juan Martin del Potro, even as the underdog against Novak Djokovic in Sunday’s U.S. Open men’s championship final.

 “I cannot believe that I have a chance to play another Grand Slam finals here, which is my favorite tournament,” said del Potro, the 2009 U.S. champion. “A big challenge as well, because I’ve been fighting with many, many problems to get in this moment.”

  At 29, del Potro has revived a career laid low by a series of wrist operations that took him away from the sport for almost three years. He nearly retired three years ago, unable to a find a surgical solution for his left wrist, which severely affected his backhand. “I got depressed for a couple of months. But it’s complete in the past now,” he said.

  “I didn’t expect to get this kind of emotions playing tennis again. Reaching finals [this only his second in a Slam event], winning titles [22 in his career on the men’s tour], having my highest ranking ever at this moment [he is currently No. 3]."

  So he’s sees nothing but positives in facing the 31-year-old Djokovic, 13 times a major tournament champion and the reigning Wimbledon titlist.

  Del Potro, with a powerful serve and forehand, theoretically is aided by facing Djokovic on the Open’s hard courts. But those courts have been playing slower than usual this year, and the nimble, athletic Djokovic is perhaps tennis’ best at sending back every ball he sees. “Playing against Novak,” said John Millman, who lost to Djokovic in the quarterfinals, “I think the guy beat a brick wall once, because he makes you work for every point and it’s relentless.”

  Djokovic himself had to deal with a wrist surgery in February and can empathize with del Potro, whom Djokovic said he likes “very much, not just as a player but as a person, someone I respect very much. We all felt for his struggles with injuries that kept him away from the tour.”

  With a 14-4 head-to-head record against del Potro, Djokovic must be considered the favorite. But the Arthur Ashe Stadium crowd, which will include several of del Potro’s friends from his Tandil, Argentina, home, likely will liven the atmosphere with more “Del Po” chants. Serbian fans have not been in quite the same evidence for Djokovic.

  Also, del Potro has demonstrated the danger he presents to the best players. His decision over defending champion Rafael Nadal on Friday, when Nadal retired with knee tendinitis down by two sets, was the 10th time del Potro has beaten the world’s No. 1 player. No other player never to hold the top spot, since the inception of the tour rankings in 1973, has done that.

  “It will be a difficult match because we are close friends,” del Potro said. “For sure, we both want to win. Novak has won [this year’s] Wimbledon already. He is playing so good.

  “But, I don’t know. When I played Roger [Federer] nine years ago [in the Open final], he was the favorite to win, as well. I will try to make the surprise again. I’m here. I’m excited to keep surprising the tennis world, as I did with myself. I’m happy just to be a tennis player again.”

  In the meantime, he is making his pals from Argentina happy. “Enjoy the final,” he told them. “Because, after the final, you have to go home. And go back to work.”