Spain beat Brazil 2-1 in a thrilling start to the revamped $10million tournament that features 18 countries with ties also set to take place in Sydney with the final scheduled for January 7th.

World number ones Novak Djokovic and Iga Swiatek are among the big names who will be in action in the coming days as they warm up for the opening Grand Slam of the new year which will run from Jan. 14-28 in Melbourne.

Norrie overcame a dip midway through his Group C clash with Alex de Minaur to prevail 6-4, 2-6, 7-6 at the packed RAC Arena and snap his nine-match losing streak against opponents ranked inside the world's top 20.

De Minaur's British girlfriend Boulter then settled the tie with a 6-2 6-4 victory over the fit-again Ajla Tomljanovic, who missed the majority of last season due to a knee injury that required surgery.

Alejandro Davidovich Fokina and mixed doubles partner Sara Sorribes Tormo earlier beat the pair of Beatriz Haddad Maia and Marcelo Melo 6-4, 7-5 in the decider of the Group A tie between Spain and Brazil.

United Cup debutant Davidovich Fokina put Spain up 1-0 by defeating Thiago Seyboth Wild 6-4, 6-0 in the first match of the 2024 season, dominating his opponent from the baseline and not facing a break point throughout the contest.

But Brazil hit back through world number 11 Haddad Maia, who downed Sorribes Tormo 7-6, 6-2 in a rematch of their marathon French Open fourth-round clash earlier this year.

"To come back and play with Sara, I think we had a great time on court and we enjoyed a lot," world number 26 Davidovich Fokina told reporters.

"We didn't care... obviously we care, but the result was like the last thing. We were enjoying out there, just to keep improving also."

The Czech Republic will meet China and Poland play Brazil in Perth on Saturday while the Netherlands take on Norway and Italy face Germany in Sydney.