Former world No. 4 Kei Nishikori advanced to the quarterfinals of the Japan Open tennis tournament Saturday with a convincing 6-2, 6-3 victory over Australia's Jordan Thompson.The host country favorite, currently ranked 200th, converted five of his seven break points while allowing Thompson to break his serve only once at Ariake Colosseum.Thompson, who has risen to a career-high rank of 29th, was facing Nishikori after he upset third-seeded Casper Ruud of Norway in the first round."This win is big for me," the 34-year-old Nishikori said. "I'm the most surprised, and my coaching staff must b…READ FULL ARTICLE