Team USA have completed a 5-0 semi-final drubbing of Poland to emphatically underline their United Cup title credentials.
A 6-7 (5-7) 6-4 10-6 mixed doubles victory for Taylor Fritz and Jessica Pegula over veteran Lukasz Kubot and teenager Alicja Rosolska round out another American clean sweep in Sydney.
The United States will enter Sunday's final against either Italy or Greece having dropped only two rubbers out of 20 in their four ties so far at the new mixed teams' event.
The tie was already sealed before the mixed after Fritz edged Hubert Hurkacz 7-6 (7-5) 7-6 (7-5) in two tight tiebreak sets earlier on Saturday to give the Americans an unassailable 3-0 lead in the best-of-five-rubber semi-final.
Madison Keys then routed Magda Linette 6-4 6-2 to remain unbeaten in four Cup singles matches before Fritz and Pegula rallied from a set down to complete the whitewash under a closed roof at Ken Rosewall Arena.
Team USA had enjoyed a commanding 2-0 overnight buffer after singles wins on Friday for Pegula and Frances Tiafoe.
Pegula stunned world No.1 Iga Swiatek 6-2 6-2 before Tiafoe outclassed world No.245 Kacper Zuk 6-3 6-3 to extend his undefeated record at the competition to five matches, including one mixed win with Pegula.
"It was great to get the win today to get us through," Fritz said.
"I had no doubt that if I were to lose that the rest of the team would have come through.
"I've played with Team USA a lot but I think it's a huge advantage this time having the girls in our team because it just makes the whole team so much stronger.
"So I'm super excited going into the finals and I think we've been favourites all week."
Pegula has won three straight singles matches, including her rousing victory over Swiatek, as well as four mixed encounters since dropping her opening rubber against Petra Kvitova.
But the world No.3 was still relieved to see Fritz finish off Poland and avoid a potentially nerve-wracking deciding mixed match.
"I was very stressed. I was doing the stress thing with the ball and my hands were like freaking out," Pegula said.
"It was awesome for Taylor to clinch that in a really, really tight match against a great player.
"Kudos to him. That definitely took the pressure off the rest of us for the rest of the day."
Italy enjoyed a 2-0 lead entering session two of the second semi-final following singles wins on Friday night for Martina Trevisan and Lorenzo Musetti.
Trevisan upset world No.6 Maria Sakkari 6-3 6-7 (7-5) 7-5 in a three-hour, 15-minute epic before Musetti crushed world No.803 Stefanos Sakellaridis 6-1 6-1.
Greece's world No.4 Stefanos Tsitsipas must beat fellow grand slam runner-up Matteo Berrettini in Saturday's first singles match, starting at 5pm AEDT, to keep the tie alive.
Even if Tsitsipas wins, the lowly-ranked Despina Papamichail will be at long odds to force a deciding mixed doubles rubber with an upset victory over Lucia Bronzetti.
