Poland returned to the semi-finals of the United Cup mixed team tournament for a third successive year after hard-fought singles victories in Sydney handed them an unassailable 2-0 lead over Britain on Thursday. Iga Swiatek settled the tie after an almighty battle with Katie Boulter, prevailing 6-7(4) 6-1 6-4 as last year’s runners-up booked a last-four clash with Kazakhstan in the $10 million tournament before the Jan. 12-26 Australian Open. “I’m just exhausted,” said Swiatek after the near three-hour marathon at Ken Rosewall Arena. “I’m happy that I won, so that I don’t need to play mixed doubles. This match was crazy, so many changes of momentum.” Swiatek squandered a 4-1 lead in the opening set, which her opponent clinched in 74 minutes after an inspired comeback. But the world number two was not to be denied as she romped through the second set and shrugged off a right leg issue in the decider to outlast Boulter. “I thought I had it under control in the first set but I got tight. I didn’t want to repeat the same mistake in the third and I took four pain killers,” Swiatek said. “A lot hurt, but I’m happy that I won and for sure I’m going to need the day off tomorrow. “If they give me space to lie down (in the dugout) I’ll take a nap … I think I’ll just go to the locker and die.” Hurkacz clinched a tight opening set when Billy Harris sent a backhand long in the tiebreak and then stepped up a gear late in the second set to seal a 7-6(3) 7-5 victory and put his team ahead 1-0 in front of delighted fans. “Definitely super pleased with myself,” Hurkacz said after his first singles win of the tournament. “Today was a really difficult battle with Billy … This win is so crucial to get more confidence and get another match in.” United States, the 2023 champions, have already reached the semi-finals and will await the winner of Friday’s quarter-final clash between Italy and the Czech Republic. The final takes place on Sunday.