Juan Martin del Potro has reflected on a "great" 2013 season following his exit from the ATP World Tour Finals in London.
The Argentine fell 4-6 7-6 7-5 to Roger Federer in yesterday's final group game.
However, four more titles this year - taking his career total to 17 - saw him finish in the top five, with Federer dropping out of the four-man monopoly at the top of the rankings.
Del Potro said that he will be working hard to close the gap on Rafael Nadal, Novak Djokovic, Andy Murray and David Ferrer ahead of him.
"For this year, my goal was trying to play in the same level [as] the top guys," the 2009 US Open winner told reporters. "I am the only player who beat all of them in this season, which means something for me.
"I think I did a great season. Maybe I [will] finish in the top 5 after three and a half years. [It] is really good [to] see my ranking and my name in the top positions."
"They don't beat me easy, and I beat [them in] some tournaments. All the matches are close, but in the end they still beat me because they have a little difference. I will be working hard on that."
Federer will Nadal in the first ATP semi-final, while Djokovic takes on Stanislas Wawrinka in the second.
