Kei Nishikori believes he is getting close to the level required to win a major this year.
The Japanese fifth seed was made to work hard for a 6-4 7-6 (7-1) 6-2 win over Spain's Nicolas Almagro in the Australian Open first round on Tuesday.
Fresh from reaching the US Open final last year, Nishikori is one of the most likely men to claim his maiden grand slam title in 2015.
The 25-year-old said he was approaching the level he believes is required to win a major.
"[I'm] getting close to next level," Nishikori told a media conference.
"Obviously was really tough, tough first match. He could be seeded player, and I know he was injured, but still was tough match.
"Yeah, was a little bit windy, so we both didn't play maybe 100 per cent.
"But I was getting more balls, especially third set, and I was playing much better third set."