Kansas University junior Maria Martinez, sophomores Erin Wilbert and Ekaterina Morozova, and freshman Sara Lazarevic went undefeated in singles play to open the KU Invitational on Friday at First Serve Tennis center.

The four Jayhawks advanced to the quarterfinals in two brackets, beating players from UMKC, Saint Louis University and Illinois State University.

The second day of the three-day KU Invitational continues today at First Serve. The event is free to the public.