David Rudisha, the Kenyan athlete who earlier in the week ruled out besting his own world record in the 800 metres at the London Games, set a new world record in the final of the event on Thursday evening.
Rudisha, whose previous record stood at one minute 41.01 seconds, clocked one minute 40.91 to take the gold medal, delighting the London crowd who had waiting for more than a week so see one of the major athletics records fall.
Nijel Amos of Botswana claimed silver with one minute 41.73, despite being only 18-years-old. The bronze medal went to Rudisha's countryman Timothy Kitum, who ran a personal-best of one minute 42.52.
Britain's Andrew Osagie finished last, but still managed a personal best time of one minute 43.77.
Speaking to BBC Sport, Rudisha said: "Wow! I'm very happy. This is the moment I have been waiting for for a very long time. To come here and to break the world record is something unbelievable.
"I was well-prepared and I had no doubt about winning. Today the weather was beautiful and I decided just to go for it.
"Lord Coe is a very good friend of mine and earlier, in February, he took me round this stadium. That was good for me. I wanted to come here and make him proud."
Speaking to Reuters on Monday, the 23-year-old said: "The track is fast. It looks good."
"In this championship I don't look at the record. It is a medal that I want. Once I get the medal, toward the end of the season I can think about the record."