SYDNEY (AP) — Greece badly missed Stefanos Tsitsipas in the singles when it was beaten by Poland on the opening day of the 16-team ATP Cup tournament in Sydney. The fourth-ranked Tsitsipas was a late withdrawal from his match with ninth-ranked Hubert Hurkacz, who went on to beat replacement Aristotelis Thanos 6-1, 6-2 to give Poland an unassailable 2-0 lead. Greece then gained some consolation when Tsitsipas combined with Pervolarakis in the doubles to overcome Szymon Walkow and Jan Zielinski 6-4, 5-7, 10-8. Argentina’s Diego Schwartzman and Spain’s Roberto Bautista Agut led their respective teams to comfortable victories earlier. And Serbia, playing without Novak Djokovic, beat Norway 2-1.