Britons Andy Murray and Heather Watson registered singles wins on a sweltering day in Perth to help give Great Britain a 3-0 Hopman Cup whitewash of Germany.
On a morning when temperatures rose to 36 degrees, Watson beat Sabine Lisicki 6-3 6-4 before Murray overcame Alexander Zverev 6-3 6-4.
The pair then teamed up for a 6-3 6-4 win in the mixed doubles.
Britain still need France to beat Australia Green in the last group game to reach Saturday's final.
British women's number two Watson, 23, secured an impressive straight-sets win over former Wimbledon finalist Lisicki.
Lisicki, ranked 32 in the world, made a strong start on serve in the first set only for Watson to make the decisive break at 4-3 and serve out the set to 15.
The second set was more comfortable for world number 55 Watson as she broke Lisicki twice to seal a third career win over her former training partner.
"It was a really good match," Watson said. "She's a tough opponent and a great server, so I knew that holding serve would be very important.
"I did a shorter off-season, but more intense, this year," she added. "I feel like this is the fittest and strongest I've ever been."