MELBOURNE, Australia (AP) -- U.S. Open runner-up Kei Nishikori was circumspect about his quarterfinal loss at the Australian Open on Wednesday, saying there's nothing wrong with getting to the final eight of any Grand Slam tournament.
He's done it three times now -- two of them at Melbourne Park -- but he realizes there is plenty of room for improvement.
Nishikori had few answers for Stan Wawrinka's shot-making and excellent serving in a 6-3, 6-4, 7-6 (6) loss to the defending champion.
At the U.S. Open last year, Nishikori beat Wawrinka in the quarterfinal in five sets before beating Novak Djokovic in the semis to reach his first Grand Slam final. He lost to Croatia's Marin Cilic.
"It wasn't really a bad week," Nishikori said of the past 10 days in Melbourne. "It's not easy getting to a quarterfinal at Grand Slams. But I have to keep doing this ... playing tough all the time, playing a lot of matches, especially at Grand Slams."
Nishikori said after two relatively easy set wins for Wawrinka, he felt more comfortable in the third set as he challenged the Swiss player more.
"I could be a little more aggressive than the first and second set," Nishikori said. "I was mixing up serve and volleys. My serve was much better than first couple sets because I was making more first serves."
In the tiebreaker, Wawrinka looked to be cruising but the Japanese player saved match point after match point with a combination of great shots and errors by Wawrinka.
Nishikori made the biggest error at the wrong time, however, attempting a drop shot from the back of the court that bundled into the net. That set up another match point for Wawrinka, which he converted with an ace, his 20th of the match.
"Yeah, the tiebreaker was really close," Nishikori said. "If I could get that one (the attempted drop shot), it might change the whole thing. But he was serving really well until end of the set, so I think I have to give him credit."
Nishikori said he had spoken to his coach, former French Open champion Michael Chang, right after the match on ways to improve his game, and how Chang might continue to help him.
"I've been working with him for one year now," Nishikori said. "I see a lot of improvement, not just tennis, outside, too. Mentally I get more stronger. I think physically I'm little more fit than before. So I'm really happy right now."