Petra Kvitova has battled into round two of the US Open with a three-set victory over world number 92 Misaki Doi.
Kvitova, seeded seventh, looked on course for a straightforward afternoon when she took the opening set 6-2 inside 36 minutes.
However, Doi capitalised on a number of errors from the Czech in the second as the Japanese levelled the contest 6-3.
Two breaks in the decider saw Kvitova open up a 4-0 lead before she was able to see out the match 6-1.
The former Wimbledon champion will now face Serbia's Bojana Jovanovski for a place in round three.
