Kei Nishikori tamed big-serving American Sam Querrey 7-6 (7-3), 6-3 to reach the quarterfinals of the Japan Open on Wednesday.
Defending champion Nishikori stood toe-to-toe with the 198-cm Querrey, winning all his service games under an open roof in windy conditions at Ariake Colosseum.
Nishikori prevailed in a tiebreaker to win a first-set slugfest, before breaking his world No. 50-ranked opponent early in the second set and going on to close out the match in one hour, 13 minutes.