Vera Zvonareva survived a scrappy second set to slip into the third round of Wimbledon with a 6-1 7-6 win over fellow Russian Elena Vesnina.
The second seed, runner-up to Serena Williams last year, struggled with her serve in the second set, trading breaks with Vesnina before clinching victory.
Zvonareva will next face surprise 2010 semi-finalist Tsvetana Pironkova.
Fourth seed Victoria Azarenka was in ruthless form as she swept aside Iveta Benesova of the Czech Republic 6-0 6-3.
Azarenka, of Belarus, will now face Daniela Hantuchova, the 25th seed.
Of the other seeds in action, Andrea Petkovic, Agnieszka Radwanska, Julia Goerges, Flavia Pennetta, Dominika Cibulkova and Jarmila Gajdosova all progressed but there was one notable casualty.
The eccentric American Bethanie Mattek-Sands, seeded 30, failed to produce a performance to match her eye-catching outfit and she fell to Japanese qualifier Misaki Doi 6-4 5-7 7-5.