Two-time Wimbledon champion Petra Kvitova overcame a late wobble to set up a third-round encounter with fourth seed Paula Badosa.
The Czech had won 10 of the first 12 games and was leading 5-1 in the second set before Romania's Ana Bogdan won five games in a row.
Kvitova eventually stemmed the flow to take it to a tie-break, going on to win the match 6-1 7-6 (7-5).
Meanwhile, Spaniard Badosa beat Romania's Irina Bara 6-3 6-2.
Kvitova, 32, is one of just three former champions left in the women's singles draw along with 2019 champion Simona Halep and 2018 winner Angelique Kerber.