London - As the sun set on the opening week of Wimbledon, just about the only seeding that truly signified something was No. 1.

That's the number beside the names of Serena Williams and Novak Djokovic, who turned in nearly perfect performances back-to-back Saturday on Centre Court to cap nearly perfect runs to the fourth round at the All England Club, while chaos reigned all around them.

In the final match of the fortnight's first half, played with the roof closed and lights glowing to make sure it would get done as darkness approached, defending champion Williams used eight aces and 11 return winners to power past 42-year-old Kimiko Date-Krumm of Japan 6-2, 6-0 in 61 minutes.

"She didn't lose energy, and her game, I think, is getting better, day after day. Not better in general, but adapting to the surface. Everything is getting better," said French coach Patrick Mouratoglou, who has been working with Williams over the past year, when she is 77-3. "So now let's enter into the most important part of the tournament. ... Now the matches are going to get tougher and tougher."

Might not necessarily have been a fair fight, considering that Date-Krumm is ranked 84th and was the oldest woman to reach the third round at Wimbledon in the 45-year Open era. Never better than a semifinalist at a Grand Slam tournament, she played Williams evenly for about three games, before the 16-time major champion took over.

"She has so much power, speed," Date-Krumm said. "She has everything."

Williams' easy win followed the 6-3, 6-2, 6-2 victory over 28th-seeded Jeremy Chardy of France turned in by 2011 champion Djokovic, who compiled a remarkable ratio of 38 winners to three unforced errors. The Serb's initial miscue of his own doing did not come until the third set's sixth game, when he double-faulted while ahead 4-1, 40-love.

"Everything went my way," Djokovic said. "I did everything I wanted to do."

Both he and Williams could say that about the way they handled matters throughout Week 1.

Williams has won all six sets she's played, allowing her opponents a total of 11 games. Djokovic has won all of his nine sets, dropping 29 games.

"You don't want to play your best tennis in the first round and continue to go down. I feel like I try to play better as each match goes on," said Williams, whose 34-match winning streak is the longest for a woman since older sister Venus had a run of 35 in 2000. "I try to find out something I can improve on from each match so I can do it better in the next round."

In other words: Look out, Sabine Lisicki, the 23rd-seeded German who will meet Williams on Monday for a quarterfinal berth. Up next for Djokovic after the middle Sunday's traditional day of rest is another German, 13th-seeded Tommy Haas, the 35-year-old who is enjoying a career renaissance and eliminated Feliciano Lopez of Spain 4-6, 6-2, 7-5, 6-4.

Take a glance around, and a high seeding has mattered very little, with the notable exception of No. 2 Andy Murray, Djokovic's potential foe in the final. Indeed, in many cases, any seeding at all has guaranteed nothing whatsoever. The men's Nos. 3, 5, 6, 9 and 10 are all gone, including Roger Federer and Rafael Nadal, with their 29 combined Grand Slam titles. The women's Nos. 2, 3, 5, 7, 9 and 10 are out, too, including four-time major champion Maria Sharapova and two-time Australian Open winner Victoria Azarenka.

Even during a pair of victories Saturday, both No. 4-seeded players, David Ferrer and Agnieszka Rawdwanska, looked shaky. Ferrer, the French Open runner-up this month, was treated for blisters on his right foot while coming back to beat No. 26 Alexandr Dolgopolov of Ukraine 6-7 (6), 7-6 (2), 2-6, 6-1, 6-2. Radwanska, who lost to Williams in last year's Wimbledon final, was pushed to three sets by 18-year-old American Madison Keys before winning 7-5, 4-6, 6-3.

The highest-seeded man other than Murray on his half of the field is No. 20 Mikhail Youzhny, who will play the 2012 U.S. Open champion and Wimbledon runner-up after defeating Viktor Troicki 6-3, 6-4, 7-5.

Otherwise, Saturday's winners on that side of the men's draw were 130th-ranked Lukasz Kubot of Poland, who beat No. 25 Benoit Paire 6-1, 6-3, 6-4; 80th-ranked Kenny de Schepper of France, who defeated No. 22 Juan Monaco 6-4, 7-6 (8), 6-4; and 54th-ranked Fernando Verdasco of Spain, a 6-2, 6-4, 6-4 winner against Ernests Gulbis.

Things have generally been less hectic on Djokovic's portion of the tournament, but No. 9 Richard Gasquet lost 7-6 (7), 5-7, 7-5, 7-6 (5) to 20-year-old Bernard Tomic, whose father has been barred from tournaments after being accused of head-butting Tomic's hitting partner.

There isn't a lot of company for Williams in the major championship department, either. Two women with one apiece advanced Saturday, though: 2011 Wimbledon winner Petra Kvitova and 2011 French Open winner Li Na.

Otherwise, just as with the men, there are some fresh faces among the women. That includes 19-year-old Laura Robson, the first British woman to reach Wimbledon's fourth round since 1998; 19-year-old Monica Puig of Puerto Rico; and 20-year-old Sloane Stephens of the U.S., who'll face Puig on Monday.