The number one seed and overwhelming favourite for a sixth title at the All England Club was at her merciless best on Centre Court against her 42-year-old opponent who, like almost every other player on the tour, could do little but admire the American.
Williams wrapped up a 6-2 6-0 win - the 'bagel' being the 14th she has handed out this year - under the roof, with the match a late switch to the arena the 31-year-old has dominated for the last decade.
The latest career landmark caught Williams by surprise.
"That's awesome, I had no idea, wow!" was Williams' assessment of her achievement when she was told about it.
"On Centre Court, what better place is there to win 600 matches?"
One of the women Williams stopped on her way to the title last year, Petra Kvitova, also won today, getting the better of Ekaterina Makarova in a match carried over from last night.
Shorn of the pressure of being the defending champion, as she was 12 months ago, Kvitova has flourished so far and closed out a 6-3 2-6 6-3 success.
"I have some good things in my game this year which really feel like 2011," the Czech said.
"But I always drop off a little bit. I hope I can stay more up than down."
There was joy for the British fans today as Laura Robson recovered from a set down to beat Marina Erakovic on Court Two, while the up-and-coming American, Sloane Stephens, was also successful.
Stephens is one of a number of players, including Robson, to have given the women's draw a youthful tint, and she beat Petra Cetkovska 7-6 (7/3) 0-6 6-4 today.
Nineteen-year-old Monica Puig awaits Stephens on Monday and the two know each other's game well having played out of the same academy in Florida when they were juniors.
"I've known her a really long time and I am looking forward to the match," Stephens said.
"We once played each other when we were 12, but I don't think that counts for much now!"
Like Puig, Robson and Stephens, American Madison Keys is highly regarded but the 18-year-old's run was halted by last year's runner-up Agnieszka Radwanska in three sets.
Keys held her own for much of the match but lost her serve early in the decider and was swiftly put away by the Pole who won 7-5 4-6 6-3.
Roberta Vinci, the 11th-seeded Italian, also made her way through to Monday's play by seeing off Dominika Cibulkova, while Sabine Lisicki booked an appointment with Williams by getting the better of Australian Samantha Stosur.
Few will give Lisicki a chance, but having beaten Maria Sharapova last year she knows how to play the role of the underdog.
"I was in this situation last year when everybody was saying Sharapova was the favourite. I like that," the German said.
Li Na also went through, beating Klara Zakopalova 8-6 in a decider, while Estonian Kaia Kanepi made sure it will be she who meets Robson as she knocked out Alison Riske. Today's other match ended with Tsvetana Pironkova ousting Petra Martic.