The 29-year-old did not have things all her own way against the Swiss player, who was making her debut, but came through safely enough to set up a second-round meeting with Kateryna Bondarenko.
Williams said: “It’s a special moment when you walk back as defending champion on that court, throw those balls up for the first point. It’s a really great feeling.
“Wimbledon, for me, has just been a place of great success and pure joy, so many wins here in singles and doubles. I feel very good here and I take advantage of that feeling.”
Top seed Dinara Safina also moved through, although she was pushed hard by Lourdes Dominguez Lino before triumphing 7-5 6-3.
The Russian is bidding for her first grand slam title having reached the final of the first two majors of the year in Australia and France only to lose each match in straight sets.
Ninth seed Caroline Wozniacki came up against a player who made her Wimbledon debut before the Dane was even born.
Wozniacki, 18, is a dark horse for the title after winning the AEGON International at Eastbourne on Saturday but she was given a grass-court lesson by 38-year-old Kimiko Date Krumm in the first set before turning things around to win 5-7 6-3 6-1.
Sixth seed Jelena Jankovic was another big name to go through, the Serbian battling past Germany’s Julia Goerges 6-4 7-6 (7/0).
Jankovic has endured a miserable season thus far but feels surviving a testing match could be the boost she needs. “I need to compete, I need to be in a little bit tougher situations just to get myself going,” she said.
“I think I get a lot of confidence from passing these kind of rounds.”
Jankovic will play Iveta Benesova in the second round after the Czech defeated Britain’s Katie O’Brien 6-2 5-7 6-4.
Seventh seed Vera Zvonareva was pushed all the way by another home wild card, Georgie Stoop, but eventually prevailed 7-6 (7-0) 4-6 6-4.
The match had been called off at one-set all last night because of darkness.
Three seeds did perish yesterday, with Alize Cornet, Sybille Bammer and Anna Chakvetadze all falling at the first hurdle.
Frenchwoman Cornet, seeded 22nd, lost 3-6 6-0 6-4 to Russia’s Vera Dushevina, 29th seed Bammer was beaten 4-6 6-4 6-2 by qualifier Melanie Oudin while 32nd seed Chakvetadze fell 4-6 7-6 (7/4) 6-2 to Sabine Lisicki.
Surprise Australian Open semi-finalist Samantha Stosur, seeded 18th, was also taken to three sets but came through 6-4 6-7 (6/8) 6-2 against Bethanie Mattek-Sands while 19th seed Na Li was a 7-6 (7/5) 6-0 winner against Galina Voskoboeva.
It was a different story for crowd favourite Jelena Dokic, though, as she wobbled after a strong start to lose 3-6 7-5 6-2 to Tatjana Malek.
Dokic, who burst onto the scene at Wimbledon as a 16-year-old in 1999 by beating former champion Martina Hingis in the first round, needed treatment for dizzy spells during the match. Two-time quarter-finalist Nicola Vaidisova, who has slipped to number 67 in the world rankings, also went out after a 6-4 6-7 (5/7) 6-4 defeat by Rossana De Los Rios, who now faces Safina.