Ivo Karlovic moved into the second round of the Memphis Open with a 7-6 (7), 6-3 victory over Lukas Lacko on Tuesday.
Sam Querrey also advanced to the second round by upsetting No. 7 seed Benjamin Becker 4-6, 6-2, 6-1. Querrey, the 2010 champion, won his first match of the year after opening with three losses.
Kei Nishikori of Japan beat American qualifier Austin Krajicek 4-6, 6-3, 6-4 on Friday night in the quarterfinals of the Memphis Open.
Nishikori, ranked fifth in the world, shook off eight double-faults and struggled with unforced errors off his backhand. But he improved to 11-1 in Memphis by beating his friend in their first career meeting on tour.
"Obviously, I didn't play my best tennis, but I still won today," Nishikori said. "That's really important, I think. I won't play every match my best tennis. I think it's a very good win today because he was playing good tennis."