Kei Nishikori decided not to play last week's Masters 1000 tournament in Monte Carlo because he did not want to overplay on clay. The world No. 5 is playing Barcelona this week, and he will also play Madrid and Rome.

Nishikori, the top seed in Barcelona and defending champion, would like to meet eight-time tournament champion Rafael Nadal. En route to the title last year, Nishikori did not get to face Nadal, who lost to Nicolas Almagro in the quarterfinals. Nishikori later led Nadal in the Madrid final, but was forced to retire in the third set. He has not beaten Nadal in seven attempts.

"My goal is always to beat Rafa, though he has beaten me seven times already. I think I am getting closer every match," said Nishikori. "He is great player especially on clay. It’s a really tough challenge."

The 25-year-old said that the younger ATP players are improving, but the older top players are still winning against the entire field.

"It's great to come into the Top 5. I know, it's not easy to keep this position," Nishikori said. "Top 4 is very good, especially [Novak] Djokovic, who is winning almost all the tournaments he plays. However, Milos [Raonic] and I are getting closer and it's good for tennis to have some competition.

"There are so many things I have to do to improve my ranking. I have to be tougher, I have to improve my consistency and concentration, especially on important points. There are so many things to do, but I feel I am getting closer to beating them.''