The American was dumped out by Croatian Donna Vekic 6-1 6-3 in what was her first match since the French Open final last month - the highest casualty of the opening day.
"I think probably it would be helpful a few more years for the boys to really remember".
Back in 2011, there was the weird situation of Williams hiding in her panic room when testers arrived at her LA mansion, dialling 911 as she believed them to be intruders.
"If that's testing everyone five times, let's do it. Let's be a part of it".
Apart from adjusting to her role "as a working mom", the seven-time champion also had to get used to hearing something "new" as she was addressed as "Mrs Williams" for the first time at the grasscourt major following her marriage to Reddit co-founder Alexis Ohanian a year ago.
"Not only do I expect to win, I expect to win emphatically".
Her first was at the French Open last month, where Williams had to pull out ahead of the fourth round with an arm injury, having suffered it as a result of playing singles and doubles in Paris.
"You know, it still doesn't register that I'm married actually", she added.
Williams, a 23-time grand slam champion, is chasing the all-time women's record of nine Wimbledon singles titles, held by Martina Navratilova. "I'm very excited to see her attempting an incredible comeback, this time with a baby. I'm completely so far away.' I guess they decided it was a missed test, which really doesn't make sense", Williams said.
But everything else was familiar for the Swiss star who cruised past world number 57 Lajovic in just 79 minutes. Just due to the numbers, it looks like I'm being pushed out.
The 25th seed had to battle from a break down in the second set but went on to win five games in a row to set up a second-round encounter against either Tereza Smitkova or Viktoriya Tomova.
In the women's draw, Serena's sister Venus overcame a slow start to claim a 6-7 (3) 6-2 6-1 win over Swede Johanna Larsson.
"I didn't play my best but I'll get there".
Wozniacki arrives at Wimbledon on the back of victory at the Nature Valley International and opened her campaign with a 6-0 6-3 demolition of Varvara Lepchenko.
"Maybe if I play a little bit better in the beginning, it could be a little bit different".
"How is it I'm getting tested five times?"
"The tougher balance, for me, is to be able to spend time away from my son and be OK with taking, sometimes, time for myself, which is a struggle sometimes, because I really want to spend every second with him", said Azarenka, who faces No. 7 seed Karolina Pliskova next.
Three-time Grand Slam victor Stan Wawrinka returned to the All England Club in style, ousting sixth-seeded Bulgarian Grigor Dimitrov 1-6 7-6 (3) 7-6 (5) 6-4.
In the women's event, there were wins for Czech seventh seed Karolína Pliskova who defeated Britain's Harriet Dart 7-6 (7/2), 2-6, 6-1 and 10th seeded American Madison Keys, a 6-4, 6-2 victor over Ajla Tomljanovic of Australia.