Williams also won her match on Saturday

Chanda Rubin had given the USA a 2-1 lead, coming back from a set down to beat Katarina Srebotnik 5-7 6-3 6-4.

Amelie Mauresmo wrapped up victory for title holders France over Germany by beating Anna Lena Groenefeld 6-2 6-3.

Kim Clijsters helped Belgium beat Croatia and Russia, Spain, Austria, Argentina went through but rain held up Italy and the Czech Republic in Lecce.

Clijsters, who played her first match after five weeks out through injury on Saturday, beat Karolina Sprem 6-1 6-3 and Els Callens beat Jelena Kostanic 6-2 3-6 6-4.

Russia's winning point against Australia in Moscow came as Vera Zvonareva beat Samantha Stosur 6-2 6-3.

Austria's Barbara Schett recovered from 4-1 down to win the first set 7-5 against Martina Sucha and, although the Slovakian stormed through the second 6-1, the Austrian regained control for a 7-5 1-6 6-2 victory.

And Japan's withdrew from a third-set tie-break in a crucial reverse singles match against Paola Suarez of Argentina because of leg cramps, sending Argentina into the quarter-finals.

Italy and the Czech Republic were forced to conclude thier match on Monday after torrential rain, with Francesca Schiavone beating Klara Koukalova 1-6 6-2 6-2 to give the hosts victory.

World Group first round results:

France 5-0 Germany
Nathalie Dechy bt Anna Lena Groenefeld 6-7 (1-7) 6-1 6-4
Amelie Mauresmo bt Barbara Rittner 6-1 6-2
Amelie Mauresmo bt Anna Lena Groenefeld 6-2 6-3
Emilie Loit bt Julia Schruff 6-2 6-2
Dechy and Mauresmo bt Groenefeld and Julia Schruff 6-2 6-0.

Russia 4-1 Australia
Anastasia Myskina bt Samantha Stosur 6-4 6-1
Svetlana Kuznetsova bt Alicia Molik 6-4 3-6 6-4
Anastasia Myskina lost to Anastasia Myskina 3-6 3-6
Vera Zvonareva bt Samantha Stosur 6-2 6-3
Kuznetsova and Elena Likhovtseva bt Molik and Rennae Stubbs 6-2 3-6 7-6 (9-7)

Austria 3-1 Slovakia
Barbara Schett bt Janette Husarova 4-6 6-1 6-4
Barbara Schwartz bt Ludmila Cervanova 3-6 7-6 (7-1) 6-2
Barbara Schett bt Martina Sucha 7-5 1-6 6-2
Husarova lost to Sybille Bammer 6-3 6-2

Belgium 3-1 Croatia
Kim Clijsters bt Jelena Kostanic 6-1 4-6 6-1
Kirsten Flipkens lost to Karolina Sprem 2-6 0-6
Kim Clijsters bt Karolina Sprem 6-1 6-3
Els Callens bt Jelena Kostanic 6-2 3-6 6-4.

Slovenia 1-3 United States
Tina Pisnik bt Lisa Raymond 7-5 7-5
Katarina Srebotnik lost to Venus Williams 1-6 2-6
Tina Pisnik lost to Venus Williams 3-6 1-6
Katarina Srebotnik lost to Lisa Raymond 7-5 3-6 4-6

Italy 3-1 Czech Republic
Francesca Schiavone bt Barbora Strycova 5-7 6-1 6-0
Silvia Farina Elia bt Klara Koukalova 6-3 7-6 (8-6)
Maria Elena Camerin lost to Barbora Strycova 5-7 6-3 5-7
Francesca Schiavone bt Klara Koukalova 1-6 6-2 6-2

Argentina 3-0 Japan
Gisela Dulko bt Ai Sugiyama 6-3 6-4
Paola Suarez bt Akiko Morigami 6-4 6-0
Paola Suarez bt Ai Sugiyama 6-7 (6-8) 6-3 7-6 retired