Former world number one Serena Williams gave the United States a commanding 2-0 lead over Belarus in their Fed Cup tie on Saturday after top ranked Victoria Azarenka was unable to compete for the eastern Europeans because of a sore lower back.
American Christina McHale defeated Belarus` Anastasia Yakimova 6-0, 6-4, then Williams beat Olga Govortsova 7-5, 6-0 in the World Group II tie indoors at Worcester, Massachusetts.
Australian Open champion Azarenka will be eligible to face Williams, if she responds to treatment, in the first match of the reverse singles on Sunday. A doubles match is also scheduled for Sunday.
Williams has been hampered by an injured ankle that she sustained before the Australian Open, but said it was improving.
"It`s feeling fine," she told reporters. "I`m surprised as how well it`s doing considering. I`m actually really excited about the progress."