In this year's Wimbledon playoffs, the top two women's seeds (Serena Williams and Li Na) have been ousted in the first three rounds. Going into the round of 16, there are only six players seeded 1-16, four seeded 17-32, and six are unseeded.
That looks like a "low seeded" final four rounds to me. Is it common to have only three "top five" seeds and six unseeded contestants in the round before the quarter finals?
This kind of result in a grand slam event isn't that uncommon at all, really. One thing you've got to understand about the sport of tennis is that among the top 150-200 players in the world - they can all beat each other if one player isn't playing that well and the other is. The margin between winning and losing is really small and easily tilted in favor of one player given a break of serve or two. There are even matches where the losing player wins more total points than the winner does.
Also keep in mind that for major events (like Wimbledon) the singles draw begins with 128 players and so there are more rounds (and matches) for players to compete in, thus the chances of a seeded player losing goes up compared to say, the average tournament with just a draw of 32 or 64.
Going into the semifinals, the contestants were seeded Number 3 (Simona Helep), Number 6 (Petra Kvitova), Number 13 Eugenie Bouchard, and Number 23 (Lucie Safarova). That is, two from the top 8, one from the next 8, and one from the bottom 16. That is a reasonably normal result for the finals.
The "challengers" that won early-round matches against the likes of Serena Williams and Li Na were eliminated in the middle (fourth and fifth) rounds, as were several other unseeded players that had easy draws the fist three rounds. The "giant killers" turned out not to be giants in their own right, and fell to high seeded players who were not having bad days.
