The last 24 hours at Wimbledon have produced two of the most dramatic first-week matches in recent years.
We've got so used to the top three having things their own way that it was a real surprise to see all three men dropping sets.
In Lukas Rosol, Rafael Nadal ran into an opponent who had the match of his life. What a display it was — the fifth set particularly was nerveless. He was inspired by the occasion, the atmosphere — you name it.
Nadal was not at his very best, but nor was he far from it. It was simply a freak result.
If you thought that would be a reminder to Nadal's rivals that there are no easy matches, but you wouldn't have known it today.
Novak Djokovic may just have underestimated his Czech opponent Radek Stepanek, and after losing the first set, he had to raise his game considerably to put any thoughts of an upset to one side.
As for Roger Federer, he really did come close to going out against Julien Benneteau in the final match on Centre Court.
I don't think Federer took Benneteau lightly — the Frenchman had beaten Federer the last time they played, after all - but this is a pattern that has started to develop in Federer's play.
He can breeze past some opponents, and then suddenly find himself in real trouble against others.
Federer doesn't change his tactics a great deal — two sets down to Benneteau, he seemed to believe that he simply had to do what he had already been doing ,but better. That meant cleaner groundstrokes, hitting faster and harder.
Eventually, he got over the line, and that is what matters here.
There have been occasions when the likes of Djokovic, Nadal and Federer have dropped sets in the early rounds of Grand Slams (although rarely at the same time like this) but it is unusual for it to have any bearing on their display in the next round.
Look how close Djokovic got to going out at the French Open — and yet he kept on grinding out the results until he reached the final.
Federer and Djokovic are still on a collision course for the semi-final, and my hunch is still that the Swiss will get through that one.
As for Andy Murray, he must be really rather happy with the way his side of the draw is playing out.
Nadal is gone in the semi-finals, Grigor Dimitrov is gone from the next round, and then today, another potentially tricky opponent, Milos Raonic, bowed out to Sam Querrey.
Raonic could have been a real handful for Murray in the fourth round, but I was covering his match against Querrey for television, and he was disappointing.
Murray might get a little extra boost of confidence from these results, but they are no use to him unless he does his part and keeps on winning.