LONDON—After losing to Roger Federer in three sets at the ATP World Tour Finals, Juan Martin del Potro notes the differences that separate him from the elite players. The Argentine scored wins over Federer, Rafael Nadal, Andy Murray, and Novak Djokovic this year, but failed to reach the final of a major or win a Masters 1000 title.
“They don’t beat me easy, and I beat [them at] some tournaments,” del Potro said. “All the matches are close, but in the end they still beat me because they have a little difference yet. Maybe I need to be strong mentally or strong physically. But with my tennis, I think I’m okay. I have still things to improve like my volleys or my approaches to the net. But in the end they make difference mentally or physically. I will be working hard on that.”