By winning the City Final on Wednesday night in Sydney with a tidy 4-1 score over Great Britain, the Americans soon made the short commute back to their hotels, looking forward to an off-day. Meanwhile, in Brisbane and Perth, four nations battled to join them in Friday’s United Cup semifinals in Sydney.

In the end, Poland defeated Italy and Greece upended Croatia -- with both ties decided by mixed doubles featuring four of the world’s best singles players. Italy, by virtue of percentage of sets son, was the next-best squad and will join them. Poland and Italy made their way 500-plus miles down the east coast of Australia from Brisbane, while Greece had to navigate more than 2,000 miles from Perth, situated on the west coast.

The matchups and overall record after three ties: U.S. (13-2) vs. Poland (10-5) and Greece (11-4) vs. Italy (10-5).

Here’s a closer look at the two semifinals:

United States vs. Poland

The numbers say Poland has a 6-3 head-to-head advantage in the four singles matches, but four of those wins belong to Iga Swiatek over Jessica Pegula.

All four victories came last year in big spots -- the Miami semifinals, Roland Garros quarterfinals, US Open quarterfinals and San Diego’s semifinals. Only San Diego went three sets. In terms of ranking, this is the class of all the semifinal matches, World No.1 Swiatek versus the third-ranked Pegula.

Two of the other singles matchups -- Hubert Hurkacz-Taylor Fritz and Magda Linette-Madison Keys -- are deadlocked at 1-all. The difference for the United States could be Frances Tiafoe, who is a combined 6-0 in singles and mixed doubles. Tiafoe is ranked No.19, 241 spots higher than Poland’s Daniel Michalski, who has gone 0-3 in singles play.

If the teams split the four singles matches, it could come down to a blockbuster mixed doubles confrontation between Swiatek and Hurkacz (2-0) and Tiafoe and Pegula (3-0). The Polish duo clinched their victory over Italy to advance to the semifinals.

“It was Iga,” Hurkacz said. “She was just playing really amazing, and she was returning Lorenzo [Musetti]’s serve really powerful, and that was helping a lot to put some pressure on the net. There wasn’t a lot of tactics there.”

Added Swiatek: “I don’t consider myself a leader. I’m still kind of getting used to it, but I also got used to the pressure, especially last year. I’m trying to cut it off on my matches to just focus on my game, and it’s going pretty well. Hopefully I’m going to be able to do that on my next matches.”

Friday, Jan. 6
Ken Rosewall Arena

[2] Iga Swiatek (POL) vs [3] Jessica Pegula (USA), 1 p.m.

Head to head: Swiatek, 4-1

[2] Daniel Michalski (POL) vs [3] Frances Tiafoe (USA), to follow

Head to head: 0-0

Saturday, Jan. 7
Ken Rosewall Arena

[2] Hubert Hurkacz (POL) vs [3] Taylor Fritz (USA), 10 a.m.

Head to head: 1-1

[2] Magda Linette (POL) vs [3] Madison Keys (USA), to follow

Head to head: 1-1

Mixed doubles match: Teams TBD

Greece vs. Italy

Once, again the head-to-head records here could be deceptive.

Overall, Greece holds a 3-1 advantage in the teams’ head-to-head single’s records. Heading into the semifinals, No.4-ranked Stefanos Tsitsipas leads No.16 Matteo Berrettini 2-0. Tsitsipas prevailed at the 2019 Australian Open and, two years later, in Rome.

Perhaps more relevant is Tsitsipas’ 6-0 record in singles and mixed doubles (with Maria Sakkari). That equals Sakkari and Tiafoe for the best mark among all remaining players.

Elsewhere, you can make a case for Italy. Martina Trevisan holds a 1-0 edge over Sakkari, a three-set match at Roland Garros in 2020. That was on the red clay in Paris, a surface that is far friendlier to Trevisan’s game. A fast hard court in Sydney might be another matter.

Similarly, Despina Papamichail has a 1-0 record against Lucia Bronzetti -- but that came five years ago at an ITF $15,000 event. And then there is the disparity between the rankings of Lorenzo Musetti (No.23) and his opponent, Michail Pervolarakis (No.506).

Greek captain Petros Tsitsipas was asked if he’d allow a small celebration after his No.1-seeded team took out Croatia to advance to the semifinals.

“No celebrations until we lift the trophy,” he said.

Italian Captain Vincenzo Santopadre didn’t yet know the fate of his team when he met the press following the loss to Poland.

“We just have to wait,” he said. “I say what I said before, we have to be happy and continue -- if there is the chance to continue, it would be really nice because I’m sure that if it happens, we will enjoy again.”

Friday, Jan. 6
Ken Rosewall Arena

[1] Maria Sakkari (GRE) vs. [5] Martina Trevisan (ITA), 7 p.m.

Head to head: Trevisan, 1-0

[1] Michail Pervolarakis (GRE) vs [5] Lorenzo Musetti (ITA), to follow

Head to head: 0-0

Saturday, Jan. 7
Ken Rosewall Arena

[1] Stefanos Tsitsipas (GRE) vs [5] Matteo Berrettini (ITA), 5 p.m.

Head to head: Tsitsipas, 2-0

[1] Despina Papamichail (GRE) vs [5] Lucia Bronzetti (ITA), to follow

Head to head: Papamichail, 1-0

Mixed doubles match: Teams TBD