The world number one-ranked Iga Swiatek led Poland into the quarterfinals of the United Cup mixed teams tennis tournament on Monday, winning both her singles and doubles matches. Swiatek took the court under pressure, needing to win her singles match against Spain's Sara Sorribes Tormo to keep the tie alive. Alejandro Davidovich Fokina had given Spain a 1-0 lead with a 3-6, 6-3, 6-4 comeback victory over No. 9-ranked Hubert Hurkacz. But Swiatek beat Sorribes Tormo 6-2, 6-1 to force a deciding mixed doubles match. Swiatek and Hurkacz then needed little more than half an hour to wrap up the tie with a 6-0, 6-0 win to make Poland the first country through to the quarterfinals. In Sydney, three-time Grand Slam singles finalist Casper Ruud kept Norway's quarterfinal chances alive with similar victories in the singles and mixed doubles against Croatia. Donna Vekic gave Croatia an early 1-0 lead with a 7-5, 3-6, 6-3 win over unheralded Malene Helgo. But Ruud then beat Borna Coric 6-4, 6-1 to send the tie to a decisive mixed encounter, which Norway claimed in a match tiebreaker.