Kim Clijsters' first taste of Olympic action lasted little more than an hour as she saw off Italy's Roberta Vinci on Saturday.
Clijsters' saw off Vinci to reach the second round of the women's singles at Wimbledon.
London is both a Games debut and swansong for Belgian Clijsters, who will retire for the second time after the US Open in a month's time.
She has struggled with injuries this season and was hampered by an abdominal strain at Wimbledon three weeks ago, where she crashed out in the fourth round to Angelique Kerber.
But she looked in very good form today, racing through the first set and then edging out Vinci in a closer second to win 6-1 6-4 and become the first singles victor of the Olympics.
In the second round, Clijsters, a three-time grand slam champion, could meet fifth seed Sam Stosur of Australia, who faces Spain's Carla Suarez Navarro on Saturday afternoon.
Clijsters is relishing the chance to compete at the Games and was very happy with her form against Vinci.
She said: "It's a great feeling knowing that I'm here because there were moments in the last year-and-a-half where I definitely thought about retiring and not even getting to the Olympics.
"So I'm happy that I stuck with it and that I kept working hard. I'm happy that I'm healthy and that I got to play a good match in the first round.
"I still feel that whenever I step out on court and I feel good physically, if I play good tennis, I can beat a lot of good players. With that attitude, I'll go until I play my last match. That's a good attitude. It's something that I need to have."
Wimbledon champion Serena Williams returned to Centre Court three weeks after winning her fifth title at the All England Club, and she had an illustrious name in her box in the form of US First Lady Michelle Obama.
Williams had a potentially tricky draw against former world number one Jelena Jankovic of Serbia but she went into the match on a run of 11 straight victories and ran out a comfortable 6-3 6-1 winner.
Jankovic's countrywoman Ana Ivanovic fared better, the 11th seed defeating talented young American Christina McHale 6-4 7-5.
Williams, who next meets Poland's Urszula Radwanska, was inspired by her esteemed guest and gave the First Lady a thumbs-up at the end of her match.
"They asked me did I mind if she sat in the family box," said Williams. "I was like, 'Of course not. Please, it would be my honour.' I love Michelle, so it was good.
"I gave her a thumbs-up just to acknowledge that I knew she was here. Obviously it was impossible not to see her but it was cool."
Two of last year's grand slam champions are already out of the tournament, with fifth seed Stosur and 11th seed Li Na both losing today.
Australian Stosur went down in an epic against Carla Suarez Navarro, the Spaniard winning 3-6 7-5 10-8, while China's Li was beaten 6-2 3-6 6-3 by Slovakia's Daniela Hantuchova.
