World number three Karolina Pliskova battled into the second round of the US Open in a topsy-turvy straight-set victory over Tereza Martincova.

Pliskova beat her Czech compatriot 7-6 (8-6) 7-6 (7-3) in a match that saw 12 breaks of serve, excluding both tie-breaks.

The 27-year-old, who reached the final at Flushing Meadows in 2016, will play Mariam Bolkvadze or Bernarda Pera next.

Elsewhere, world number two Ashleigh Barty is a set down to Zarina Diyas.