Tokyo - Kei Nishikori thrilled his home fans as the US Open finalist posted a 6-3, 6-4 opening victory over Ivan Dodig on Wednesday to reach the second round of the Japan Open.
The fourth-seeded Nishikori could do no wrong at the Ariake Colosseum, where the roof waqs closed due to intermittent rain after two days of sunshine in the capital.
Nishikori, last week's champion in Kuala Lumpur, next faces Donald Young after beating the American in both of their previous ATP matches. He improved to 4-0 over Dodig, beating him for the second time this season.
Japan's top player is working to become the first Asian man to qualify for the eight-strong field at London's World Tour finals in November. Nishikori currently stands provisional sixth with five spots in the field still to be filled over the next month of regular season ATP play.
Wednesday's victory took his 2014 record to 45 wins and 10 defeats.
The Japanese spent just under 90 minutes earning his victory against an increasingly frustrated Dodig, who was short with both the ballboys and the Hawkeye computerised line calling system.
Nishikori was out-aced 6-2 by the 61st-ranked Croatian, who saved two match points in the penultimate game.
Nishikori took the opening set in 38 minutes thanks to a break for 5-3 as he took the early lead. The Japanese player went down a break, 1-3 in the second set, but levelled again with a break back in the fifth game.
The Asian, watched by famed part-time coach Michael Chang, then tacked on an insurance break for 4-3 and closed out victory three games later on his third match point as he wrong-footed Dodig to end the afternoon.
American Steve Johnson became the first man into the quarter-finals after defeating Spain's Marcel Granollers 4-6, 6-3, 6-4, a 10-ace performance for the winner which took just under two hours.