Serena Williams - winner here in 2003 and 2004 - had to come from behind to beat Angela Haynes after losing an epic firstset tie-break 14-12.
Sister Venus, the 2000 and 2001 champion, has been seeded only at 14 this year following an indifferent couple of seasons, with a quarter-final appearance at the 2004 French Open her best grand slam performance.
Despite a straightforward 6-2, 6-4 triumph over Eva Birnerova on the graveyard of champions, the 25-year-old American still looked far from the player who had dominated the All England Club at the start of the century.
But Williams said: "My career goal is still to win grand slams and every tournament that I enter."
The former champion was adamant that she did not see yesterday's scheduling to play on Court Two as a snub, saying: "What's important is to be in the draw.
"I like playing tennis and I enjoy being out there.
"I always have a good time whether I win or lose a match, that is the most important thing that team Williams does - we have fun."
Elsewhere, the 11th seeded Russian Vera Zvonareva came from behind to secure her place in the second round with a 2-6, 6-4, 6-0 victory over Marlene Weingartner, of Germany.
It was a similar story for young Slovakian Daniela Hantuchova, the 20th seed, who beat Evgenia Linetskaya, of Russia, 3-6, 6-2, 6-2.
On Centre Court French Open champion Justine Henin-Hardenne, the seventh seed, lost in three sets to Eleni Daniilidou, of Greece.
Eighth seed Nadia Petrova, of Russia, came from behind to beat Spaniard Virginia Ruano Pascual 4-6, 6-3 6-2 but American Lisa Raymond is out after losing 7-5, 6-3 to Russia's Tatiana Panova.
Mary Pierce led a clutch of French women into the second round, defeating Czech Lucie Safarova 6-3 6-4.
The 30-year-old, who enjoyed a dream run to the French Open final earlier this month, used all her experience to beat an opponent 12 years her junior.
Williams and Haynes had been training partners when they were younger, and the two-time Wimbledon champion was full of praise for her compatriot.
"I think she played unbelievable," Williams said. "She was serving really well and was focused.
"I expected a tough match because she wanted to win the first big match of her career and had nothing to lose - I had to be really focused, too.
"There was a point where I lost focus a bit in the first set and got a bit off track, but I was feeling my way through and was able to come back.
" I had to step up because she was playing really well and I had to hit the ball a bit harder."
Williams was forced out of the French Open by an ankle injury, and said she felt a bit "rusty" yesterday afternoon.
"I was feeling my way around," said Williams, who maintained playing on the 'graveyard of seeds' "did not enter my mind".