World No. 2 Iga Świątek earned the decisive point for Team Poland, defeating Britain's Katie Boulter 6-7, 6-1, 6-4 in the women's singles.
Earlier, Poland's Hubert Hurkacz outplayed Britain's Billy Harris 7-6, 7-5 in the men's singles.
Poland will face Kazakhstan for a place in the final of the mixed-teams competition, public broadcaster Polish Radio’s IAR news agency reported.
Poland beat Norway 2-1 in its first match at the United Cup tournament in Australia on Monday, and followed up with a 2-1 victory over the Czech Republic on New Year's Day.
The United Cup serves as a warm-up event for the Australian Open Grand Slam tournament in Melbourne, set to begin on January 12.
(gs)
Source: IAR, PAP, Polsat Sport