Two-time Wimbledon champion Petra Kvitova won a thriller to upset world No.3 Jessica Pegula 7-6 (8/6), 6-4 at the United Cup in Sydney on Friday, but it was not enough to take the tie as the US won 4-1.

“We keep fighting,” Kvitova said. “I think USA is such a great team with great players in the team. We are not really favorites here, but we are fighting every match, every point. That’s our team spirit.”

“It was a high-level match for a solid two hours, it got kind of physical towards the end,” Pegula said.

“She can really step into the court, hits lots of winners and hits a big ball. It’s not always easy playing someone like her first match of the season.”

In Perth Maria Sakkari and Caroline Garcia both earned victories for their respective countries, Greece and France, Sakkari beat Bulgarian Viktoriya Tomova 6-3, 6-2 and Garcia blew away Argentine Nadia Podoroska 6-2, 6-0 in an hour.

Garcia put her form down to a holiday break in Bali before arriving in Western Australia. “I was just a regular tourist out there on my own and nobody knew who I was and it was pretty nice,” she said.

Sakkari’s won gave gave Greece an unassailable 3-0 lead over Bulgaria.

“I was a little nervous in the beginning, especially being 2-0 up in the tie, I knew my match was crucial in winning the tie,” Sakkari said.

“She was very solid, but I found my game and got better.”

In other matches Harriet Dart beat Maddison Inglis 6-4, 6-4 in 1 hour and 51 minutes to secure Great Britain a 3-2 win over Australia in Sydney and Switzerland completed a 3-0 defeat of Kazakhstan in Brisbane, with captain Stan Wawrinka beating Alexander Bublik 6-3, 7-6 (7/3).

Wawrinka, who has struggled with injury of late, was in fine form. “It feels good to be back in Australia,” the 37-year-old said.

“It’s been a long time since I played here. Tonight I had a great level. I’m super-happy with how I’m playing. I had to play aggressive and push him at every opportunity.”

Italy won both singles matches against Brazil in Brisbane, Matteo Berrettini downing Thiago Monteiro 6-4, 7-6 (9/7) before Lucia Bronzetti beat Laura Pigossi 6-0, 6-2.