Poland's Iga Swiatek celebrates her win over Kazakhstan's Elena Rybakina plays a forehand in their semifinal match at the United Cup tennis tournament in Sydney, Australia.

Poland's Iga Swiatek, right, celebrates with teammates after her win over Kazakhstan's Elena Rybakina in their semifinal match at the United Cup tennis tournament in Sydney, Australia.

Kazakhstan's Elena Rybakina plays a forehand to Poland's Iga Swiatek during their semifinal match at the United Cup tennis tournament in Sydney, Australia.

Poland's Iga Swiatek plays a forehand to Kazakhstan's Elena Rybakina during their semifinal match at the United Cup tennis tournament in Sydney, Australia.

Poland's Iga Swiatek plays a forehand to Kazakhstan's Elena Rybakina during their semifinal match at the United Cup tennis tournament in Sydney, Australia.

Kazakhstan's Elena Rybakina plays a backhand to Poland's Iga Swiatek during their semifinal match at the United Cup tennis tournament in Sydney, Australia.

Poland's Iga Swiatek plays a forehand to Kazakhstan's Elena Rybakina during their semifinal match at the United Cup tennis tournament in Sydney, Australia.

Kazakhstan's Elena Rybakina plays a forehand to Poland's Iga Swiatek during their semifinal match at the United Cup tennis tournament in Sydney, Australia.

Poland's Iga Swiatek plays a forehand to Kazakhstan's Elena Rybakina during their semifinal match at the United Cup tennis tournament in Sydney, Australia.

Poland's Iga Swiatek plays a forehand to Kazakhstan's Elena Rybakina during their semifinal match at the United Cup tennis tournament in Sydney, Australia.