2016 champion Angelique Kerber beats Anna-Lena Friedsam in straight sets

A solid performance from 2016 US Open champion Angelique Kerber saw her beat compatriot Anna-Lena Friedsam and move into the last 16.

Kerber started strongly before the players had to go off briefly due to inclement weather.

When play resumed Friedsam briefly threatened when she broke back to get to 3-2 down but Kerber responded emphatically, winning the next three games to take the set.

The 17th seed then broke in the first game of the second set but Friedsam dug deep to force some errors from Kerber and take a break of her own.

In the end a tiebreak was required to separate them as Kerber struggled a bit for fluency and Friedsam gave a better account of herself than she had in the first.

Even the tiebreak was tight, indicative of the second set, but it was Kerber who prevailed and progressed to the next round.

Elsewhere 14th seed Anett Kontaveit eased through as she beat Kaja Juvan 6-4, 6-1.

The Estonian is 9-2 since the season began.

However there was an upset as 21-year-old Marketa Vondrousova, the 12th seed, was beaten 6-2, 6-1 by Aliaksandra Sasnovich.

Croatia's Petra Martic is through after beating Kateryna Bondarenko 6-3, 6-4.

20-year-old Russian Varvara Gracheva produced a stunning comeback from 6-1, 5-1 down to beat Kiki Mladenovic in straight sets.

Sixth seed Petra Kvitova is through after a 7-6(3), 6-2 win over Kateryna Kozlova.