With his frustrating wrist injury finally behind him and the U.S. Open looming large next month, the smile is back on Juan Martin Del Potro's face as he prepares for this week's ATP event in Los Angeles.

The towering Argentine played just three tournaments last year because of an injured right wrist but all that is largely forgotten and he is excited to be back in form with the U.S. hardcourt season ahead of him.

"It has been a very long while (with) my wrist injury but now I'm okay," former U.S. Open champion Del Potro told reporters while preparing for his opening match at the Los Angeles International.

"I'm getting better with my tennis, with my mind and my problems are in the past. I am not thinking about my wrist, about different injuries that I had last year.

"Now I have everything to improve, starting with my ranking, with my game, with my body and with my physicality."

Del Potro has won two ATP titles this season -- at Delray Beach and in Estoril -- and has climbed from a lowly 484th in the rankings in early February to 19th this week.

"I just want to improve my game and be at the top as soon as I can," said the 22-year-old, who won the Los Angeles International in 2008 and his first grand slam title the following season at the U.S. Open.

"I know it's a long road, a very tough road but I still believe in my game. I am very confident with my level at this moment."

Del Potro, seeded second in Los Angeles, will take on either American James Blake or Germany's Michael Berrer in the second round on Wednesday at the LA Tennis Center.

TOUGH COMEBACK

"I am lucky to be top 20 at this moment but it was really tough for me to come back, especially in the beginning of the season when I was in the Australian Open and I lost in the second round," the Argentine said.

"Then I came here to the U.S. to play indoors and I played the first round (in Memphis) against John Isner, a very difficult player to start the first round.

"But if you don't have the rankings after an injury, it can happen like maybe what can happen in this tournament if I play against Blake in the second round. But that's tennis...."

Del Potro plans to take a week off after the Los Angeles International before competing in Montreal and Cincinnati to wind up his preparations for the season's final grand slam, the U.S. Open in New York.

"I am very excited to come back to New York," said the Argentine, who had to withdraw from his U.S. Open title defense last year because of his wrist injury.

"If I could start to play (the U.S. Open) tomorrow I would," he added with a huge grin. "But first I have very important tournaments before.

"This tournament (in Los Angeles) is important for me. It will be my first tournament after the clay and grass season. And I have very good memories here. I won my first hardcourt tournament here in L.A."

American Mardy Fish, who beat fellow American Isner to defend his Atlanta Tennis Championship title on Sunday, is the top seed in Los Angeles. Like Del Potro, Fish has a bye into the second round.

New York Los Angeles Germany U.S.