Australian Open champion Sofia Kenin and Serena Williams gave the United States a 2-0 lead over Latvia in their Fed Cup qualifier on Friday.
Kenin blitzed Anastasija Sevastova 6-2 6-2 to get the USA up and running in Everett, while Williams battled past 2017 French Open winner Jelena Ostapenko 7-6 (7-4) 7-6 (7-3).
Barely a week after breaking through for her first grand slam title in Melbourne, Kenin was in the American state of Washington to represent her country.
The world number seven and 21-year-old surged past Sevastova before 23-time major winner Williams eventually saw off Ostapenko in the second rubber to improve her win-loss record at the Fed Cup to 14-0.
"It's been a long journey. It wasn't easy," Kenin said. "But I was super happy to come here and play with the team."
It was a tough day for former world number one and two-time grand slam champion Naomi Osaka, who was reduced to tears after losing to unheralded Spaniard Sara Sorribes Tormo.
Osaka, whose title defence at Melbourne Park was sensationally ended by teenager Coco Gauff in the third round, was swept aside 6-0 6-3 against Sorribes Tormo.
Japan trail Spain 2-0 in the tie after Carla Suarez Navarro accounted for Misaki Doi 6-3 6-4.
Switzerland, led by Belinda Bencic, Germany and Slovakia also boast 2-0 leads against Canada, Brazil and Great Britain respectively.
The other ties – Netherlands against Belarus, Romania versus Russia and Belgium against Kazakhstan – are deadlocked at 1-1.