Serena Williams of the United States thrashed Russia's Maria Sharapova 6-0 6-1 in 63 minutes to win the women's singles gold medal at London 2012.
Williams dropped 17 games all week and has won all of her 17 matches since on 29 May.
It was the most comprehensive Olympic women's singles final win.
French Open champion Sharapova takes the silver medal and world number one Victoria Azarenka of Belarus bronze.
"I didn't think I would be this happy," said Williams, who plays in the doubles semi-finals with her sister Venus later on Saturday.
"Oh my gosh, I got the gold. I've never played better. Playing against someone like Maria you have to be at your best. I knew that, so it was like I had nothing to lose.
"I never expected gold in singles. I was so happy with my doubles golds [in Sydney 2000 and Beijing 2008]. I thought, 'If my career's over I have my gold medal and now I have everything.'
"I have singles, doubles, actually everything there is to win in tennis. Where do I go from here?"
Sharapova added: "Serena played some incredible tennis, with the form she was in during Wimbledon and afterwards.
"With every match she has played she has played great, she has improved and become better, and that showed today."
Top seed Azarenka beat Maria Kirilenko of Russia to take bronze.
"It is just like everything came off my shoulders," said the Australian Open champion. "It was an incredible match.
"I felt so nervous because it is not very usual for a tennis player once you lose to come back the next day and play, so it was incredibly hard but I am so glad I did it and it was worth it."
Serena later teamed up with sister Venus to clinch a place in the women's doubles final with a 7-5 6-4 over Russia's Maria Kirilenko and Nadia Petrova.
They will play Andrea Hlavackova and Lucie Hradecka in Sunday's final after the Czech Republic pair upset US top seeds Liezel Huber and Lisa Raymond 6-1 7-6 (7/2).