A quarter-finalist at Melbourne Park last year, the 23-year-old has mapped out a three-year plan to win a grand slam and his jaw-dropping success at last October's Japan Open underlined the threat he poses.
"Kei is a superstar," said Milos Raonic after the Canadian had suffered the dreaded 'bagel' in the third set of their final in Tokyo. "He has the potential to do great things."
Nishikori told Reuters that overcoming suffocating pressure to win the Japan Open had given him the belief he can break into the top 10 and walk with the game's giants.
"I think winning a grand slam is possible," the swashbuckling Nishikori said after beating Raonic 7-6 3-6 6-0 in the ATP 500 event to win his second career title.
"I probably played the best tennis of my life. Breaking into the top 10 is the goal now."
Winning this year's Australian Open would be one of the biggest shocks in tennis - and with Novak Djokovic, Roger Federer and Andy Murray among the heavy hitters blocking his way the odds are stacked against him.
The world number 18 will be seeded 17th in Melbourne because of Rafa Nadal's absence and he believes he is getting closer after topping a quality field in Tokyo headed by U.S. Open and Olympic champion Murray.
He showed flashes of genius to win the title, demonstrating the potential to become a serious contender at future grand slam tournaments, often leaving opponents gaping in dismay.
"I feel I've got a little closer to them," Nishikori said of the Big Four -- Federer, Djokovic, Murray and Nadal.
Nishikori burst onto the scene as an 18-year-old by winning in Delray Beach as a 244th-ranked qualifier in 2008 and is already a major celebrity in Japan.
His maiden title was the first by a Japanese man since Shuzo Matsuoka beat Todd Woodbridge in Seoul in April 1992.
However, he will need to bulk up, his career already blighted by various injuries, most notably in 2009 when he needed elbow surgery and feared he might not play again.
Ankle and knee issues have also plagued Nishikori, who retired from his semi-final against Murray in the Australian warm-up event in Brisbane with a left knee injury.
Nishikori, who had jumped out to a 4-1 lead over the Briton before losing the first set, was then forced to pull out of the Kooyong Classic but was still confident he would be fit to play at Melbourne Park.
"It's not bad -- let's cross the fingers and hopefully it will be okay," he told reporters on Tuesday.
The Australian Open markets itself as the grand slam of the Asia Pacific and in Nishikori, who lost to Murray in the last eight last year, they finally have a male contender for the world's most populous continent to cheer on.
Asked after his Tokyo triumph if he was seen as a threat to the world's elite, Nishikori blushed and said: "The other players will look at me differently now."