Serena Williams defeated Lesia Tsurenko 6-3, 6-2 on Sunday to send the United States back into the Fed Cup World Group with victory over Ukraine.
The U.S. now holds an unassailable 3-0 lead in the best-of-five series after singles victories for Williams and Christina McHale on Saturday.
Williams was making her first Fed Cup appearance on foreign soil in more than a decade.
Tsurenko frustrated Williams early on with accurate hitting from the baseline. After giving up a break, she pressured Williams' serve, but couldn't convert two break points. Williams broke again to take the set.
The Ukrainian battled hard in the second, but Williams' powerful returns led to three more breaks to secure the win.