The 30 year old smashed her way to gold in a 6-0 6-1 victory over Maria Sharapova at Wimbledon.
Before yesterday, the most one-sided final had been in 1920 when Suzanne Lenglen beat Dorothy Homan 6-3 6-0.
Williams is the first person to win the golden slam in both singles and doubles and the first person to do it in singles since Steffi Graf won all five titles in 1988. She lost just 17 games in the entire tournament.
The Wimbledon champion said: "I've really been training hard and the injuries have been disastrous for me.
"I feel like I could have had more slams, but I was fortunate enough to survive what I went through and it made me a better person and maybe a better player.
"Who knows if I would have had this desire to do well and to play otherwise?
"I wanted it more and I think the health struggles made me want it more."
The 14-times Grand Slam winner is now on a 17-match winning streak and finished the match with two aces, asserting her utter dominance.
Her victory matched her 6-1 6-0 win over another Russian, Vera Zvonareva, in the third round.
She jumped up and down and danced with delight as she clinched the Olympic title.
Williams has lost just five games in the three Olympic finals she has won: 2000 Sydney doubles, 2008 Beijing doubles and 2012 London singles.
She said: "Being Olympic gold champion, Golden Slam singles and doubles, that's pretty awesome. I would have been happy whether I'd got silver or gold because it's such a great achievement to get on that medal stand.
"But obviously I've won a gold. It's a big moment. I've always wanted to win a gold.
"I was really focused today and when you're playing a great player like Maria you've got to come ready to play. She had a chance of winning a golden slam and I did too.
"I don't know if it was domination it was just me being really focused and I think the grass suits me, it just all came together.
"I've done something no one else has done so I'm really excited about it."
Sharapova, 25, was competing in her first Olympic Games and received enthusiastic support from the Wimbledon crowd despite being on the receiving end of the one-sided encounter.
After the match, the Russian said: "I am so proud of my accomplishment here. It's magnificent to be at the Olympic Games for the first time and leave with a silver medal.
"It was such a great experience, certainly a tough tournament, and I can't wait for the four years to come around to get another chance."
During the medal ceremony the US flag came loose in the wind, but it did not fluster Williams, who said: "Obviously it wasn't intentional, it was just really windy. Hey, it's life."
If she and her sister Venus win the doubles final today they will both have four gold medals, which no-one else has achieved before.