AFP, ADELAIDE, AustraliaAngelique Kerber’s preparations for this year’s opening Grand Slam were dealt a blow yesterday when she was forced to retire from the Adelaide International with back pain. 1, who won the Australian Open in 2016, pulled out when behind 6-3, 2-0 in her second-round clash with Ukraine’s Dayana Yastremska. Second seed Simona Halep is to take on Aryna Sabalenka after the Belarusian booked her spot 7-6 (7/4), 6-2 over American qualifier Bernarda Pera. In men’s play, Russian Andrey Rublev, who won the Qatar Open over the weekend, beat American Sam Querrey 6-3, 6-3 to move into a last-eight clash against Britain’s Dan Evans. South African qualifier Lloyd Harris also advanced to the quarters with a 7-6 (7/5), 6-3 win over Laslo Djere.
