Kei Nishikori of Japan
Kei Nishikori of Japan reacts during his semi-final tennis match against Novak Djokovic of Serbia at the ATP World Tour Finals at the O2 Arena in London November 15, 2014. Reuters

The first Japanese man who reached Grand Slam finals, Kei Nishikori revealed that one of his goals this upcoming season will be to reach the semi-finals in all Grand Slam tournaments in 2015. According to Nishikori, one of his goals is to at least reach the semi-finals in all four Grand Slams.

Last January, the Japanese tennis superstar fell in the fourth round after losing to the Spaniard Rafael Nadal at the Australian Open. "I was able to come away from that match with a good feeling," Nishikori said. "That boosted my confidence and I changed to a more attacking brand of tennis."

In April, following the Australian Open, Kei Nishikori won his first career clay court title in Barcelona. Afterwards, he managed to reach the finals at the Madrid Masters, where he started leading 3-0 but was eventually won by Rafael Nadal.

Now, the 25-year-old is ranked fifth in the world rankings and he managed to join the elite ATP World Tour Finals in London, which only features the top eight world ranked tennis players. The Japanese verbalised that it is not a problem that his offseason what relatively short because of joining the ATP World Tour Finals. Thus far, he is working with his coach and focused on overcoming his second-serve issues.

The first Grand Slam tournament will be the Australian Open but prior to that, Nishikori will play in the Brisbane International as a warm up, where he is hoping for positive results. He further claimed that he finds it easy to play in Australia.

Just recently, Andre Agassi, who recently played with Kei Nishikori in an exhibition match in Tokyo, rated Nishikori as a strong chance to the upcoming Australian Open 2015. In fact, he was labelled by the former tennis legend as one of the greatest shot-makers ever. Moreover, Agassi tipped the Japanese to become the first Asian male to win a Grand Slam because he is incredibly fast and dynamic. He said that Nishikori is among the few players whom he would pay to watch.