Top seed Ana Ivanovic needed just 58 minutes to beat Rossana de los Rios 6-1 6-2 in her opening match at Wimbledon.
The French Open champion wrapped up the first set in 23 minutes on Centre Court and was rarely troubled by her Paraguayan opponent in the second.
The 21-year-old Serb, who reached the semi-finals last year, will face Nathalie Dechy in the second round.
Former champion Serena Williams came through a testing clash with Estonia's Kaia Kanepi to seal a 7-5 6-3 victory.
The world number 36 pushed Williams hard in both sets, but the sixth seed held her nerve to complete the win.
Williams, who sported a stylish jacket with a wraparound leather belt for the warm-up, briefly looked in danger of becoming the first big-name victim of the tournament as Kanepi came out with all guns blazing.
Kanepi raced into a 40-0 lead on Williams's serve in the opening game, but set the tone for her brave, but ultimately unsuccessful, challenge by losing her way to allow her opponent to hold.
And after pushing Williams all the way, Kanepi faltered at just the wrong moment with a double fault on set point costing her the opener.
Two-time champion Williams went 4-1 up in the second, but was made to work hard to seal the win.
"She was a tough opponent," she told BBC Sport. "She served big and hit bigger than me, but it's good to play someone like that early on to get into the swing of things straight away.
"I'm in good form and I'm just looking forward to playing lots more matches here."
Ivanovic was happier with her performance, saying: "I think I played quite well, especially for the first game on grass."
Asked if she felt different to begin the tournament as the world number one, she said: "I do actually, but at the same time it's very challenging for me, it's something new and exciting. Coming as the top seed, lots of people expect you to win.
Kuznetsova has reached the last eight three times in the last five years
"When you tell people you want to go match by match they think it's such a cliché, but it's not.
"Becoming number one gives you more pressure but it's a reflection of your own ambition. If you look at it that way, it can be very motivating."
Fourth seed Svetlana Kuznetsova of Russia was in trouble after losing the first set against qualifier Mathilde Johansson of France.
The 2004 US Open winner was also a break down in the second, but she battled back to win 6-7 (5-7) 7-5 6-3.
Amelie Mauresmo, the Wimbledon champion in 2006, had no such problems and put a disappointing run of form behind her - she has slipped to 33 in the world rankings and is seeded 22nd - to beat Ashley Harkleroad 6-4 6-3.
Last year's beaten finalist Marion Bartoli was similarly convincing in her 6-2 6-4 victory against Sabine Lisicki.
However, 12th seed Patty Schnyder of Switzerland crashed out, losing 6-4 3-6 6-1 to Australian Casey Dellacqua.
Virginie Razzano was the first seed to exit on Monday after the 27th ranked Frenchwoman lost 0-6 6-2 6-4 to Russia's Evgeniya Rodina.
Seventeenth seed Alize Cornet, 19th seed Maria Kirilenko and Dominika Cibulkova, the 30th seed, also went out at the first stage.
Qualifier Anastasia Pavlyuchenkova, who at 16 is the youngest player in the women's draw, beat France's Cornet 7-6 (8-6) 7-6 (7-4), China's Jie Zheng knocked out Slovakian Cibulkova 6-4 6-3 and Vera Dushevina saw off fellow Russian Kirilenko 6-3 6-3.
Eighteenth seed Nicole Vaidisova had no such problems though, as she cruised past fellow Czech Zuzana Ondraskova 6-2 6-2.
Eighth seed Anna Chakvetadze came back from losing the first set to oust Stephanie Dubois of Canada 2-6 6-1 8-6, while 14th seed Agnieszka Radwanska, the Eastbourne champion, saw off Iveta Benesova 6-3 6-0.
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