Cameron Norrie defeated Alex de Minaur in a tight three-set thriller before Katie Boulter held off a strong comeback from Ajla Tomljanovic to make it 2-0.

The awkwardness of Aussie de Minaur coming up against girlfriend Boulter in the tie got even more awkward when the Aussies were rolled in front of their home crowd at the RAC Arena in Perth.

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Boulter showed no mercy to Tomljanovic, who missed 10 months of action this year due to a knee injury, beating her 6-2, 6-4 to clinch victory for Britain in the mixed teams event.

The British ran out 2-1 winners as Australia saved some honour in prevailing in the mixed doubles.

As expected De Minaur did not feature in the mixed doubles, despite him making cheeky comments about the potential of playing against his partner in the days leading up to the match.

The 24-year-old joked it would be “all business” if he did face Boulter on the other side of the net.

“I have played mixed in the past with Katie, so I know all her weaknesses,” he said.

“I’ve watched enough of her matches to know the spots to be attacking. If we step out on court, it’s just all business.”

Britain joined Spain, who beat Brazil 2-1 to begin the competition at the 18-team tournament being staged in Perth and Sydney prior to the Australian Open.

Norrie lifted his level at the end to overcome good friend and training partner de Minaur 6-4, 2-6, 7-6 (7/2), repeating a victory he earned against the Aussie at the event a year ago.

Drama swirled as De Minaur double-faulted on match point in the final tie-breaker.

South Africa-born Norrie, with family in Australia watching, ended a nine-match loss streak against Top 20 opponents as he beat de Minaur in front of a packed-out local crowd.

“I had to dig deep and play bravely in the third set,” Norrie said after a match that lasted nearly two-and-a-half hours.

“At the end of the second set he was firing and I could not match his level. “We always have great battles, I had to run a lot today. But it’s good to start the year with a win,” added the 28-year-old.

Boulter, ranked 56 in the world, was thrilled to give Britain an unassailable lead on her United Cup debut.

“I’ve been training well coming in, I’ve tried to work as hard as I could,” she said.

“This win starts the year really well. Having the entire team behind really does help you.” Earlier world number 11 Beatriz Haddad Maia got her season off to a winning start, but it was not enough to prevent Brazil losing 2-1 to Spain.

The tie came down to a deciding doubles rubber, with Alejandro Davidovich Fokina and Sara Sorribes Tormo defeating Haddad Maia and two-time Grand Slam winner Marcelo Melo 6-4, 7-5.

Davidovich Fokina got Spain off to a winning start as he dispatched Thiago Seyboth Wild 6-4, 6-0, requiring four match points to earn the first victory of the tournament.

Haddad Maia then prevailed by defeating Sorribes Tormo 7-6 (7/1), 6-2 to level the tie at 1-1.

The end of the crunch mixed doubles tie was tight, with Brazil saving a match point before falling seconds later.

“I knew I had to be calm near the end,” Davidovich Fokina said.

“I needed to focus on every point — in doubles things can change very quickly.” Spain are playing without Rafael Nadal, with the 37-year-old ending a year-long injury absence at the Brisbane International instead.

— with AFP