SYDNEY, Australia - Last week, Petra Kvitova was forced to withdraw from the Brisbane International due to a viral illness. This week, she was the beneficiary of Mirjana Lucic-Baroni's own illness after the Croat retired from their all-unseeded first round at the Sydney International after losing the first set 6-1.

Showing no ill effects, the Czech began the match in ruthless form, dropping just two points in the first three games as she blitzed Lucic-Baroni with her power.

The Croat's fairytale run to the Australian Open semifinals last year had kickstarted a fine first quarter of 2017 that culminated in cracking the Top 20 at the age of 35 in May, but an injury-hit second half had seen her win just three matches since the clay of Rome - and the World No.30 had no answers to her 27-year-old opponent at first.

Lucic-Baroni got on the board after a titanic tussle in the fourth game, holding serve after coming through two deuces - but though she carried the momentum into the next game, pushing the two-time Wimbledon champion to deuce - but Kvitova sharpened her strokes to hold on for 4-1 and break again for 5-1.

The World No.29 had little difficulty in subsequently serving out the set over an ailing opponent, and after 28 minutes Lucic-Baroni was forced to pull out.