Stan Wawrinka

Three-time Grand Slam champion Stan Wawrinka clinched just his second win of 2018 on Thursday when he defeated Slovak qualifier Martin Klizan 4-6, 6-2, 6-3 to reach the Sofia ATP quarter-finals. The 32-year-old Wawrinka, who missed six months of the 2017 season to undergo two knee surgeries after Wimbledon, will face Viktor Troicki of Serbia on Friday for a place in the semi-finals.