Double Wimbledon winner Petra Kvitova fought off a challenge from Romanian Ana Bogdan on Thursday to struggle into the third round 6-1, 7-6(5).
The Czech who lifted the title here in 2011 and 2014, cruised through the opening set but had to battle as her 111th-ranked opponent rallied from 1-5 down in the second.
Kvitova only pulled out victory in a tiebreaker after one and three-quarter hours.
The seed avoided a third loss this season to a player ranked outside the Top 100 and advanced after winning her fifth grass titles at the weekend in Eastbourne.