Second-seeded Kei Nishikori of Japan eased into the Geneva Open quarter-finals, beating Mikhail Kukushkin of Kazakhstan 6-4 6-3 on Tuesday.

World No.9 Nishikori took a wildcard entry after a wrist injury affected his claycourt season and did not drop serve against the 88th-ranked Kukushkin.

Nishikori clinched the second-round match with a well-placed forehand from the baseline.

Also Tuesday, fifth-seeded Steve Johnson of the United States advanced to the second round, winning 6-3 6-3 against Frenchman Stephane Robert.

Janko Tipsarevic of Serbia, another wildcard, beat ninth-seeded American Ryan Harrison 6-4 7-6 (7-5) in a first-round match.

With a second-round match against top-seeded Stan Wawrinka as the prize, Rogerio Dutra Silva of Brazil beat Portugal’s Joao Sousa 6-4 7-6 (7-5).

Wawrinka is the defending champion at his home tournament.