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

Ranked No. 9, Nishikori took a wild card entry after a wrist injury affected his clay-court season and did not drop serve against the 88th-ranked Kukushkin.

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

He next plays South African Kevin Anderson, who outlasted 20-year-old American Jared Donaldson 6-3, 6-7 (7), 6-2.

Also Tuesday, fifth-seeded Steve Johnson of the United States advanced to the second round, winning 6-3, 6-3 against the 37-year-old Frenchman Stephane Robert.

Johnson next plays Horacio Zeballos of Argentina, who rallied from a second-set dip to beat Dusan Lajovic of Serbia 6-4, 0-6, 7-5.

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

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

Wawrinka is the defending champion at his home tournament, a final warm-up for the French Open which he won in 2015.