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. No. 23 Andreas Seppi of Italy, meanwhile, won his seventh consecutive five-setter, edging No. 12 Kei Nishikori 3-6, 6-2, 6-7 (4), 6-1, 6-4, and 49th-ranked Ivan Dodig of Croatia moved on when Igor Sijsling retired while trailing 6-0, 6-1, 1-0, the 13th player to stop mid-match or withdraw before one, equaling a tournament high.
For a moment, it looked as if there might be a 14th when No. 8 Juan Martin del Potro hyperextended his left knee as chased a ball late in his 7-5, 7-6 (3), 6-0 defeat of Grega Zemlja. The 2009 U.S. Open went champion sprawling face-forward into the players' chairs and racket bags on the sideline.
"It was really painful," del Potro said. "I was a little scared."
Del Potro and Murray each own one Grand Slam title, the only two of the last 33 not claimed by Federer, Nadal or Djokovic.
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.
That matchup prompted this question for Stephens from a reporter: Is there pressure for you when you're playing someone in the next round who you're older than?
"Like a year, OK," Stephens said. "No, not really."
At 31, Williams is the oldest No. 1 in WTA rankings history, but she's still more than a decade Date-Krumm's junior.
"I honestly never thought I would play until my 30s, to be honest. I don't see my stopping any time soon," she said. "However, I don't see myself playing into my 40s. That's why I have so much respect for Kimiko."
They spent a good chunk of the early evening wondering where and when they would play, because their match was scheduled to be last on Court 1, where Ferrer and Dolgopolov went to a fifth set. It wasn't until 7:59 p.m., minutes after Djokovic's match ended, that the Wimbledon referee's office announced it was shifting Williams' match to Centre Court, with the roof shut and lights on.
Williams was rather dominant serving and receiving. In the first set, she delivered seven aces at up to 116 mph, at least one in each of her four services game, and hit nine return winners, at least one in each of Date-Krumm's four service games.
When it was over, Williams wagged an index finger in the air, as if to remind all she is No. 1, then exchanged high-fives with some fans.
"Every time I go out there, I tell you, I feel like anything can happen. I don't feel invincible. I feel like anything can happen," she said. "More than anything, that keeps me completely motivated."