High ranking sits uncomfortably on Nishikori's shoulders

A break-out 2014 season and a career-high ranking of five has added extra weight to Kei Nishikori's shoulders, with the US Open finalist already bearing the burden of huge expectations in his home country Japan.

Nishikori became the first man from an Asian country to reach a grand slam final at Flushing Meadows and though the 25-year-old wears the distinction with pride, he also feels the pressure to take the extra step.

Nishikori reached the fourth round of the Australian Open on Saturday with a 6-7(7), 6-1, 6-2, 6-3 win over much-improved American Steve Johnson at the Hisense Arena.

But the fifth seed still has a huge mountain to climb at Melbourne Park with top seed Novak Djokovic and defending champion Stan Wawrinka likely to stand in the way of a maiden final in Australia.

"Obviously number five is a different feeling than outside of the top 10 because you still feel a lot of confidence, but you feel other things off the court," Nishikori told reporters.

"I think I feel more pressure than before. I try not to think too much. But you obviously feel a little bit. It's still not comfortable for me to be this ranking.

"But I think I need more time to get used to it. If I can play good tennis, I think I have a lot of chance to stay here this whole year. You know, practise hard and prepare good. Hopefully I can do good this week and next week."

Nishikori will have one less distraction at Melbourne Park before his fourth-round match against David Ferrer, with Japan's national soccer team bombing out of their Asian Cup title defence in Australia.

The defending champions lost a penalty shoot-out to underdogs United Arab Emirates in Sydney on Friday much to the disappointment of huge fan Nishikori.

"Yeah, (I'm) disappointed because I think they really had a chance of winning the whole thing. So really sad to see," he said.

"I hope tennis gets bigger in Japan, Asia. But I love soccer. So I hope lot of kids start playing soccer, too."