The 21-year-old had not dropped a set on her way to becoming the first Latvian woman to reach the Wimbledon semis, but self-destructed against Kerber in an error-strewn 6-3 6-3 defeat.
The outcry over her unseeded status at the French Open-she didn't lack points for failing to win or because of injury, but rather because she was busy for over a year having a baby-led to the USTA reexamining the ranking and seeding process.
"It's insane. I don't even know how to feel because I literally didn't think I'd do this well in my fourth tournament back in 16 months", said the American, who won the 2017 Australian Open while in the early stages of her pregnancy.
"Seeing her back, it's great", said Kerber, who has lost six of eight previous matches against Williams. "I was not even trying to serve a second serve because that was pointless - so I was just going for first serve constantly", she said.
Serena's seventh Wimbledon triumph gave her an historic 22nd Grand Slam title, equalling Steffi Graf's Open era record.
Aged 20, Serena already had two Grand Slam titles under her belt, but winning her first Wimbledon crown, at the expense of her sister Venus, was her true breakthrough moment. By the end, Ostapenko had far more winners, 30-10, and far more unforced errors, 36-7.
Given Williams's domination of the sport over the past two decades, it is easy to assume that she can summon greatness at the snap of her fingers.
Today, at 36 and just 10 months removed from a hard childbirth that was followed by grave health complications, she's bemused by those who expected her to reach Wimbledon's final this year, so soon after returning to competition.
"It was quite tough but I'm happy to be through". They say you can only beat what is in front of you and she has done it superbly.
Whatever the duo is doing, it's working - Williams will face Angelique Kerber in the finals on Saturday.
She opened with a double fault and won the next point with a bludgeoning forehand of breathtaking audacity, a pattern that left the audience gasping at her free-flowing brilliance and then gasping again at her appalling blunders right through the game. She's coming back and for me also I'm coming back from 2017.
"This is not inevitable for me to be playing like this". She's also won her past 15 Grand Slam matches since the start of the 2017 Australian Open, which she won while pregnant.
Making a mockery of Wimbledon's decision to seed her a lowly 25th, Williams has powered through the draw, getting stronger with each match.
Fittingly, Williams' daughter was in the Centre Court crowd as tennis's latest super-mum dismantled Goerges like she needed to get her 10-month-old back home in time for an afternoon nap. It was tough. There was a time where I could barely walk to my mailbox.
But she couldn't keep up with Williams, who grabbed 18 of 22 points and five consecutive games to close the first set and begin the next.
A "crazy" journey that began with Serena Williams taking baby steps back into top-flight tennis following a 13-month maternity break has come nearly full circle at Wimbledon as the American stands just one win away from what would be a remarkable triumph.