After rating her first-round performance “two out of 10”, Williams is unlikely to be satisfied with her ragged display on Wednesday when she came back from a break down in each set before beating Australian Alicia Molik 7-6, 6-3.
At least Williams already has two Wimbledon trophies to her name. Fellow American Andy Roddick is still looking for his first.
Third seed Roddick, twice a finalist, has had six failed bids and he moved a step closer to his dream with a 6-3, 6-4, 7-6 defeat of Thailand's Danai Udomchoke.
Danai's defeat completed a bad day for the Asian nations. Ninth seed Martina Hingis survived two match points in her previous match but avoided any such drama in a 6-1, 6-2 thrashing of Japan's Aiko Nakamura.
China's Yan Zi, Taiwan's Hsieh Su-wei and Ayumi Morita of Japan all bowed out in the first round of the women's draw.
The Belgian's last two victims at Roland Garros, Jelena Jankovic and Ana Ivanovic, are fast becoming used to the spotlight after they were feted by thousands when they went home to Serbia following their Paris exploits.
On Wednesday, however, sixth seed Ivanovic had to make do with a more modest crowd on court 18 and surged past Melinda Czink 6-0, 7-6 in another delayed first-round encounter.
Jankovic was even more ruthless in a 6-1, 6-1 demolition of Slovakian Jarmila Gajdosova.
Williams has been tipped by many, including John McEnroe, to win the title here but she has so far failed to live up to that expectation.
With more loose shots than winners, the seventh seed began berating herself at 4-1 down in the first set.
A woman who defied the rankings to win the Australian Open in January while 81st in the world was not about to roll over, however.
Williams missed a set point on her serve at 6-5 but let out an almighty roar of ‘Come on!’ when she bagged it in the tiebreak with an ace.
She staged another fightback in the second, sealing it with what she thought was a winning volley.
Yet the contest ended in confusion when Molik, after exchanging handshakes with Williams, challenged a call midway through that final rally on the advice of the umpire.
The Australian had no option but to accept defeat when Hawkeye confirmed the line judge's verdict.
Henin also had to put her celebrations on hold when her match ended in similar circumstances.
After firing an ace to finish the contest, she had to wait for Hawkeye to verify the serve was good.
Roger Federer, who is seeking to win a fifth successive Wimbledon title, took a two-sets lead over Argentinian teenager Juan-Martin del Potro in his second round clash before heavy rain arrived to send the players scurrying off court.
If the rain relents, Britain's Tim Henman, fresh from his epic five set win over Carlos Moya in the first round, was due to face another Spaniard, Feliciano Lopez.
Pakistan's Aisam-ul-Haq Qureshi, the world 279 and who came through qualifying, has the huge task of trying to defeat former world number one Marat Safin.
Aisam is the first Pakistani player to reach the second round since Haroon Rahim in 1976.
Late on Tuesday, Indian tennis starlet Sania Mirza blasted her way into the second round, easing past Russia's Yaroslava Shvedova in straight sets.
Sania, 20, wasted no time on Court 6 as she demolished the 19-year-old Muscovite 6-0, 6-3 in 55 minutes.
However, Sania was frustrated by her opponent at 5-2 up in the final set, being pegged at deuce before world number 80 Shvedova finally won the game.
And she lost two match points in the final game before finally sealing it as the Russian misfired.
Second seed Maria Sharapova was made to work harder before beating Taiwan's Chan Yung-Jan 6-1 7-5.Shocks have been notable by their absence so far and a clutch of A-list contenders eased into the men's second round.
Serbian third seed Novak Djokovic dropped just seven games in a demolition of Potito Starace of Italy while Lleyton Hewitt, the last man to win Wimbledon before Federer took over, beat Briton Richard Bloomfield.
Argentine David Nalbandian, was too good for German Mischa Zverev while 10thh seed Marcos Baghdatis, a semi-finalist last year, beat the fading light to edge out Latvian teenager Ernests Gulbis in four sets.
Wednesday’s results (prefix number denotes seeding):
Men’s singles:
Second round: Fernando Verdasco (Spain) beat Andreas Seppi (Italy) 6-3, 6-2, 6-4; 12-Richard Gasquet (France) beat Nicolas Mahut (France) 6-4, 6-3, 6-4; 5-Fernando Gonzalez (Chile) beat Alejandro Falla (Colombia) 4-6, 6-3, 6-4, 7-6 (7-1); Janko Tipsarevic (Serbia) beat Florent Serra (France) 6-3, 6-2, 6-7 (3-7), 3-6, 6-2; 3-Andy Roddick (US) beat Danai Udomchoke (Thailand) 6-3, 6-4, 7-6 (7-3).
Women’s singles:
Second round: 3-Jelena Jankovic (Serbia) beat Jarmila Gajdosova (Slovakia) 6-1, 6-1; 18-Marion Bartoli (France) beat Olga Govortsova (Belarus) 7-5, 6-2; 16-Shahar Peer (Israel) beat Kaia Kanepi (Estonia) 6-4, 7-5; 1-Justine Henin (Belgium) beat Vera Dushevina (Russia) 6-0, 6-4; Milagros Sequera (Venezuela) beat 27-Samantha Stosur (Australia) 6-2, 5-7, 6-4; 9-Martina Hingis (Switzerland) beat Aiko Nakamura (Japan) 6-1, 6-2; Elena Vesnina (Russia) beat Emilie Loit (France) 6-1, 6-2; 7-Serena Williams (US) beat Alicia Molik (Australia) 7-6 (7-4), 6-3; Laura Granville (US) beat 20-Sybille Bammer (Austria) 6-1, 6-4.
First round: Caroline Wozniacki (Denmark) beat Anastasiya Yakimova (Belarus) 7-5, 6-2; Tatiana Perebiynis (Ukraine) beat Emmanuelle Gagliardi (Switzerland) 6-3, 6-3; Virginia Ruano Pascual (Spain) beat 22-Anabel Medina Garrigues (Spain) 6-3, 2-6, 6-2; Akiko Morigami (Japan) beat Alberta Brianti (Italy) 6-4, 6-0; Agnieszka Radwanska (Poland) beat Tsvetana Kirilo Pironkova (Bulgaria) 6-2, 6-1; 21-Tathiana Garbin (Italy) beat Yan Zi (China) 3-6, 6-2, 6-3; 29-Francesca Schiavone (Italy) beat Anne Kremer (Luxembourg) 5-7, 6-4, 6-3; 17-Tatiana Golovin (France) beat Hsieh Su-wei (Taiwan) 5-7, 6-3, 8-6; 13-Dinara Safina (Russia) beat Kateryna Bondarenko (Ukraine) 7-5, 7-6 (9-7); Meilen Tu (US) beat Edina Gallovits (Romania) 4-6, 6-2, 6-2; 12-Elena Dementieva (Russia) beat Nathalie Dechy (France) 6-2, 7-6 (9-7); Tamira Paszek (Austria) beat Barbora Zahlavova Strycova (Czech Republic) 6-4, 7-6 (7-3); 28-Mara Santangelo (Italy) beat Ayumi Morita (Japan) 6-1, 3-6, 6-3; 14-Nicole Vaidisova (Czech Republic) beat Karin Knapp (Italy) 7-6 (8-6), 6-2; Severine Bremond (France) beat Ekaterina Bychkova (Russia) 6-4, 6-4; Aravane Rezai (France) beat Shenay Perry (US) 6-2, 7-6; 6-Ana Ivanovic (Serbia) beat Melinda Czink (Hungary) 6-0, 7-6 (7-3); Iveta Benesova (Czech Republic) beat Catalina Castano (Colombia) 6-0, 7-5; Victoria Azarenka (Belarus) beat Jelena Kostanic Tosic (Croatia) 6-3, 6-1; Nicole Pratt (Australia) beat Casey Dellacqua (Australia) 6-3, 6-4; 32-Martina Mueller (Germany) beat Anna Smashnova (Israel) 6-0, 6-0.
Tuesday’s remaining results:
Men’s singles:
First round: 10-Marcos Baghdatis (Cyprus) beat Ernests Gulbis (Latvia) 3-6, 6-4, 6-3, 6-2; Gilles Simon (France) beat Marin Cilic (Croatia) 3-6, 7-5, 6-4, 4-6, 6-3; 6-Nikolay Davydenko (Russia) beat Evgeny Korolev (Russia) 7-6 (14-12), 6-4, 7-6 (7-5); Gael Monfils (France) beat Thomas Johansson (Sweden) 6-4, 7-6 (7-5), 6-2; Florian Mayer (Germany) beat Sam Warburg (US) 6-4, 6-2, 6-2; Nicolas Devilder (France) beat Mariano Zabaleta (Argentina) 6-7 (3-7), 6-4, 7-5, 6-4; Chris Guccione (Australia) beat Alex Bogdanovic (Britain) 7-6 (7-2), 6-4, 6-4; Kristof Vliegen (Belgium) beat 32-Juan Monaco (Argentina) 6-4, 6-3, 7-6 (7-3); Fabrice Santoro (France) beat Ivo Karlovic (Croatia) 4-6, 7-6 (7-4), 7-6 (7-3), 3-6, 6-4; Wang Yeu-tzuoo (Taiwan) beat Igor Kunitsyn (Russia) 6-3, 6-4, 6-7 (5-7), 6-7 (8-10), 6-2; 4-Novak Djokovic (Serbia) beat Potito Starace (Italy) 6-0, 6-3, 6-4; Amer Delic (US) beat Lukas Dlouhy (Czech Republic) 6-3, 6-4, 5-7, 6-4; Nicolas Kiefer (Germany) beat 30-Filippo Volandri (Italy) 6-3, 7-6 (8-6) 6-1; 28-Robin Soderling (Sweden) beat Olivier Rochus (Belgium) 6-3, 6-2, 6-2; 18-Jarkko Nieminen (Finland) beat Michael Russell (US) 6-3, 6-2, 7-5; Michael Llodra (France) beat Stanislas Wawrinka (Switzerland) 6-4, 6-4, 6-1; Sebastien Grosjean (France) beat Jonathan Marray (Britain) 6-2, 7-6 (7-0), 7-5; 22-Guillermo Canas (Argentina) beat Ivan Navarro Pastor (Spain) 7-6 (7-3), 6-3, 6-1; 14-Mikhail Youzhny (Russia) beat Kristian Pless (Denmark) 6-4, 6-2, 6-4; Frank Dancevic (Canada) beat Stefan Koubek (Austria) 6-2, 6-4, 6-2; Simone Bolelli (Italy) beat Guillermo Garcia-Lopez (Spain) 4-6, 7-6 (7-5), 6-4, 6-4.
Women’s singles:
First round: Sania Mirza (India) beat Yaroslava Shvedova (Russia) 6-0, 6-3; 11-Nadia Petrova (Russia) beat Vania King (US) 6-0, 6-1; 5-Svetlana Kuznetsova (Russia) beat Julia Vakulenko (Ukraine) 4-6, 6-4, 6-3; Bethanie Mattek (US) beat Vasilisa Bardina (Russia) 6-1, 6-0; 23-Venus Williams (US) beat Alla Kudryavtseva (Russia) 2-6, 6-3, 7-5; 2-Maria Sharapova (Russia) beat Chan Yung-jan (Taiwan) 6-1, 7-5; 26-Ai Sugiyama (Japan) beat Melanie South (Britain) 6-3, 6-2.—Agencies