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, 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.’’
It 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’s easy win followed the 6-3, 6-2, 6-2 victory over 28th-seeded Jeremy Chardy 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 23d-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, 4-6, 6-2, 7-5, 6-4.
Laura Robson, 19, became the first British woman to reach Wimbledon’s fourth round since 1998. Also advancing were Monica Puig, 19, of Puerto Rico, and American Sloane Stephens, 20. Puig and Stephens square off on Monday.