Juan Martin del Potro says he has a lot of work to do on his backhand as he makes a comeback on tour.
The Argentine, who has had three procedures on his left wrist, has reached the quarterfinals in Delray Beach in his return. But the 27-year-old has been visibly refraining from hitting his two-hander with pace, often slicing the ball or pushing it back into court.
Del Potro was tested more on that side against John-Patrick Smith in the second round than he was in the first round.
"I need to improve my backhand as soon as I can," he said. "He kept making me hit backhands down the line, and I don't have the confidence to do that."
While he has been successful using his big forehand to win points, del Potro knows more will be required to get back to the Top 10—and justify his nickname.
"I was playing too many slices,” he said. “It’s not my game. If I improve my backhand, I will once again be the Tower of Tandil.”
The 2009 U.S. Open champion has shown improvement since his first match. According to Hawk-Eye statistics cited by the Tennis Channel, del Potro achieved a top speed of about 62-65 m.p.h. on his backhand in his first-round match, and about 72 m.p.h. in his second-round match.
In addition, the former world No. 4 hit two backhand winners down the line in his second-round match. He was forced to come up with a little more to get the ball by his opponent at the net.
Frenchman Jeremy Chardy will be his opponent in the quarterfinals.