Tennis: Two-time champion Kerber beats Petkovic to reach last eight at Stuttgart Grand Prix

Two-time champion Angelique Kerber beat her compatriot and long-time friend Andrea Petkovic 6-2, 6-4 to ease into the quarter-finals of the Stuttgart Grand Prix on Thursday. Kerber, the number five seed, had originally been scheduled to play a first-round match, but received a bye after Simona Halep's withdrawal prompted a reshuffling of the seeds. It was Kerber's ninth win in 12 meetings with 71st-ranked wildcard Petkovic, and puts her through to the last eight in Stuttgart for the fifth time.