By Ian Ransom
MELBOURNE (Reuters) - Angelique Kerber celebrated her 29th birthday with a shaky 6-2 6-7(3) 6-2 win over Carina Witthoeft at the Australian Open on Wednesday but the world number one will have much to ponder in her title defense once the candles are blown out.
The top seed opened nervously in a three-set grind against unseeded Ukrainian Lesia Tsurenko on Monday and again suffered a meltdown when cruising toward victory on a breezy day at Rod Laver Arena.
German Kerber squandered a 2-0 lead in the second set as her plucky 21-year-old compatriot swung hard at every ball and the champion's serve crumbled in the tiebreak.
But after being broken in the opening game of the decider, Kerber rallied to 4-1 before closing out the two-hour eight-minute tussle, setting up a match against Irina-Camelia Begu or Kristyna Pliskova.
(Editing by Peter Rutherford)