Katie Boulter and Cameron Norrie beat Serena Williams and Frances Tiafoe in the mixed doubles to secure Great Britain victory over the United States in the Hopman Cup.
The British pair won 3-4 4-3 4-1 in the deciding rubber after the singles matches were split.
Earlier Norrie had upset Tiafoe 7-6 6-0, ending a miserable tournament for the 20-year-old who won just one set in his three matches.
Williams stepped up her Australian Open preparations with a straight-sets victory over Boulter to complete an unbeaten Hopman Cup campaign in the singles.
The American cooled off after a strong start but prevailed with a 6-1, 7-6 victory in 78 minutes to level the tie between the United States and GB in Group B.
Watched on by her daughter Alexis Olympia – Williams found her groove through an array of powerful forehand winners to overwhelm the 97th-ranked British player.
The 37-year-old’s win over Boulter followed victories over former top 10 player Belinda Bencic and Greece’s Maria Sakkari earlier in the week.
Williams said: “It was definitely good to play three singles matches here, and the mixed (doubles).
“It was perfect – it’s just like this in Melbourne.
“It’s the exact same sun and it gives me so many problems. After you serve, you are blind for the next two points.
“It was good to play three singles matches here, not to mention the mixed doubles.”