Coco Gauff and Anna Kalinskaya reached the semi-finals of the Berlin grass court tournament on Saturday without having to play full matches as their opponents Ons Jabeur and Aryna Sabalenka retired. With Viktoria Azarenka also winning her quarter-final prematurely the previous day when former Wimbledon champion Elena Rybakina retired with illness, the only completed last eight match at the event was Jessica Pegula’s 7-6 (7-2), 3-6, 6-3 over Katerina Siniakova. World number two Gauff saved two set points and needed 11 herself to win the first set against Jabeur 7-6 (11-9). The Tunisian then ret…