ZURICH, Switzerland -- Top seed Steffi Graf defeated Austria's Judith Wiesner, 7-5, 6-4, Friday to gain the semifinals of the BMW European Indoors tennis tournament.
Second seed Martina Navratilova enjoyed an easier time in beating No. 7 seed Magdalena Maleeva, 6-2, 6-3.
Graf, who gained her 28th consecutive victory in this event, built a 4-1 lead in the first set but then committed an unusual number of unforced errors.
'I made unaccountably many mistakes with my forehand and could not get back into the flow of the game,' Graf said. 'I played well in practice but could not translate it into the match.'
In Saturday's semifinals, Graf faces Czechoslovakia's Jana Novotna, a 6-4, 6-0 winner over compatriot Andrea Strndova. Graf defeated Novotna, 6-3, 1-6, 6-4, in last Sunday's final at Leipzig, and her career record against Novotna stands at 13-3.