Since seeds were introduced in the 1920s, it's the first time none of the top-10 have reached the women's quarterfinals at Wimbledon.
It's also the only Grand Slam tournament in the half-century professional era with zero top-10 seeds in the women's final eight. The 36-year-old American, who has spent more than 300 weeks ranked No. 1, looks superb so far.
The women's singles draw has seen a plethora of surprise results, with none of the top 10 seeds reaching the quarterfinals, a turn of events that has seen 23-time Grand Slam champion Williams become the favorite to win the Venus Rosewater Dish for an eighth time.
Roger Federer of Switzerland celebrates defeating France's Adrian Mannarino in their men's singles match, on day seven of the Wimbledon Tennis Championships, in London, Monday July 9, 2018.
Williams continues her quest for an eighth title later against Russian qualifier Evgeniya Rodina, with the victor to meet Italian Camila Giorgi, who advanced to her maiden grand slam quarter-final with a 6-3 6-4 defeat of Ekaterina Makarova. She jumped to a 3-0 lead in both sets and wrapped up the win in 62 minutes.
Bertens will meet Julia Goerges after Germany's 13th seed ousted Croatian Donna Vekic 6-3 6-2 in their fourth-round contest. She is seeded 25th after missing last year's tournament while pregnant.
"I didn't expect it, honestly", said Goerges, who lost in the first round at the All England Club each of the past five years.
The women's quarterfinals are Tuesday, with Williams vs. Camila Giorgi, two-time major champion Angelique Kerber vs.
Federer, who has won 32 consecutive sets at the tournament and held serve 81 games in a row, was asked whether he paused for even a moment to wonder why he wasn't being given more of a test.
Serena Williams has warned her Wimbledon rivals she is nowhere near her best despite powering into the quarter-finals without dropping a set.
And, just as predictably, she was in no mood to provide an answer.
"At the French Open I had all that pressure, now it's gone", former junior Wimbledon champion Ostapenko said.
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