SHENZHEN, China — Defending champion Tomas Berdych advanced to the quarterfinals of the Shenzhen Open by beating Mikhail Kukushkin of Kazakhstan 7-6 (7), 7-6 (4) Thursday.

The top-seeded Czech is trying to reach his first final of the season.

Also, Bernard Tomic defeated Ryan Harrison 6-4, 4-6, 7-5, Thomaz Bellucci beat Thomas Fabbiano 7-6 (2), 7-6 (4), and eighth-seeded Jiri Vesely eliminated Inigo Cervantes 7-6 (2), 6-3.