What a day, and what a 10,000m race.
Where to start? Well, it was the end of one era and the start of another. Haile Gebrselassie ran an incredible race, but Kenenisa Bekele ran an ever better one.
I cannot believe they ran the second 5,000m in the time they did. You saw what the injection of pace did to the rest of the pack - they just couldn't live with it.
For the first part of the race we saw the Ethiopians running a team race. Then, with six laps to go, Haile did what he has never had to do before and went to the front, like Paula Radcliffe, to win it by himself.
Bekele and Gebrselassie embrace after a stunning 10,000m final
It's the first time we've seen him have to do all the work, and I think it is a great testimony to him as an athlete that he was prepared to go out there and do it.
Suddenly the roles were reversed. Haile was in a different game. And how he responded.
The crunch point came with two laps to go. If Haile was to break Bekele, he had to do it there.
He had thrown in some fast, fast laps just before that - a 61secs and a 62secs - but Bekele just stuck with him.
When the younger man went past him with 150m to go, the old champion had nothing left to give.
He still managed to run 27 seconds for the last 200m, but Bekele looked like he could have gone six or seven seconds quicker if he had had to.
So now it is on to the 5,000m, where Hicham El Guerrouj lies in wait.
He'll have two distinctly different thoughts in his head on Monday morning.
On one hand he'll be delighted that Bekele had to run such a fast race. But on the other hand he'll have looked at that kick and taken a big, deep breath.
The women's 100m final did not disappoint either.
In new champion Kelli White we have an athlete in the class of Marion Jones. And her victory was also good news for Dwain Chambers, who shares her coach Remi Korchemny.
White's gold shows that their training group is peaking just when it matters most.
Behind her, Torri Edwards ran a wonderful race from lane one to grab silver, and for Zhanna Block to take bronze after the season she's had was simply tremendous.
Which is not a word I would use when describing the scenes we saw with Jon Drummond in the quarter-finals of the 100m.
The first thing to say is that the officials did a very poor job. You don't want to see anyone forcibly pulled off the track, but at the very least they should have walked the other athletes away.
Drummond's behaviour was disrespectful to his fellow athletes. He knows the rules.
The simplest solution when confronted with his sort of intransigence would have been to run the race with him in it, and then disqualify him as soon as it finished.
That way it's over and we can all move on.